diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 0c6f5ceb0a..a7e459a20a 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -258,7 +258,7 @@ static char **replace_token(char **lines,
 							const char *token, const char *replacement);
 static char **replace_guc_value(char **lines,
 								const char *guc_name, const char *guc_value,
-								bool mark_as_comment);
+								bool mark_as_comment, bool force_quote);
 static bool guc_value_requires_quotes(const char *guc_value);
 static char **readfile(const char *path);
 static void writefile(char *path, char **lines);
@@ -457,6 +457,8 @@ replace_token(char **lines, const char *token, const char *replacement)
  * This is used for fixing up cases where the effective default might not
  * match what is in postgresql.conf.sample.
  *
+ * If force_quote is true, always quotes the value.
+ *
  * We assume there's at most one matching assignment.  If we find no match,
  * append a new line with the desired assignment.
  *
@@ -465,7 +467,7 @@ replace_token(char **lines, const char *token, const char *replacement)
  */
 static char **
 replace_guc_value(char **lines, const char *guc_name, const char *guc_value,
-				  bool mark_as_comment)
+				  bool mark_as_comment, bool force_quote)
 {
 	int			namelen = strlen(guc_name);
 	PQExpBuffer newline = createPQExpBuffer();
@@ -475,7 +477,7 @@ replace_guc_value(char **lines, const char *guc_name, const char *guc_value,
 	if (mark_as_comment)
 		appendPQExpBufferChar(newline, '#');
 	appendPQExpBuffer(newline, "%s = ", guc_name);
-	if (guc_value_requires_quotes(guc_value))
+	if (force_quote || guc_value_requires_quotes(guc_value))
 		appendPQExpBuffer(newline, "'%s'", escape_quotes(guc_value));
 	else
 		appendPQExpBufferStr(newline, guc_value);
@@ -1215,7 +1217,7 @@ setup_config(void)
 
 	snprintf(repltok, sizeof(repltok), "%d", n_connections);
 	conflines = replace_guc_value(conflines, "max_connections",
-								  repltok, false);
+								  repltok, false, false);
 
 	if ((n_buffers * (BLCKSZ / 1024)) % 1024 == 0)
 		snprintf(repltok, sizeof(repltok), "%dMB",
@@ -1224,27 +1226,19 @@ setup_config(void)
 		snprintf(repltok, sizeof(repltok), "%dkB",
 				 n_buffers * (BLCKSZ / 1024));
 	conflines = replace_guc_value(conflines, "shared_buffers",
-								  repltok, false);
+								  repltok, false, false);
 
-	/*
-	 * Hack: don't replace the LC_XXX GUCs when their value is 'C', because
-	 * replace_guc_value will decide not to quote that, which looks strange.
-	 */
-	if (strcmp(lc_messages, "C") != 0)
-		conflines = replace_guc_value(conflines, "lc_messages",
-									  lc_messages, false);
+	conflines = replace_guc_value(conflines, "lc_messages",
+								  lc_messages, false, true);
 
-	if (strcmp(lc_monetary, "C") != 0)
-		conflines = replace_guc_value(conflines, "lc_monetary",
-									  lc_monetary, false);
+	conflines = replace_guc_value(conflines, "lc_monetary",
+								  lc_monetary, false, true);
 
-	if (strcmp(lc_numeric, "C") != 0)
-		conflines = replace_guc_value(conflines, "lc_numeric",
-									  lc_numeric, false);
+	conflines = replace_guc_value(conflines, "lc_numeric",
+								  lc_numeric, false, true);
 
-	if (strcmp(lc_time, "C") != 0)
-		conflines = replace_guc_value(conflines, "lc_time",
-									  lc_time, false);
+	conflines = replace_guc_value(conflines, "lc_time",
+								  lc_time, false, true);
 
 	switch (locale_date_order(lc_time))
 	{
@@ -1260,70 +1254,72 @@ setup_config(void)
 			break;
 	}
 	conflines = replace_guc_value(conflines, "datestyle",
-								  repltok, false);
+								  repltok, false, false);
 
 	snprintf(repltok, sizeof(repltok), "pg_catalog.%s",
 			 default_text_search_config);
 	conflines = replace_guc_value(conflines, "default_text_search_config",
-								  repltok, false);
+								  repltok, false, false);
 
 	if (default_timezone)
 	{
 		conflines = replace_guc_value(conflines, "timezone",
-									  default_timezone, false);
+									  default_timezone, false, false);
 		conflines = replace_guc_value(conflines, "log_timezone",
-									  default_timezone, false);
+									  default_timezone, false, false);
 	}
 
 	conflines = replace_guc_value(conflines, "dynamic_shared_memory_type",
-								  dynamic_shared_memory_type, false);
+								  dynamic_shared_memory_type, false, false);
 
 	/* Caution: these depend on wal_segment_size_mb, they're not constants */
 	conflines = replace_guc_value(conflines, "min_wal_size",
-								  pretty_wal_size(DEFAULT_MIN_WAL_SEGS), false);
+								  pretty_wal_size(DEFAULT_MIN_WAL_SEGS),
+								  false, false);
 
 	conflines = replace_guc_value(conflines, "max_wal_size",
-								  pretty_wal_size(DEFAULT_MAX_WAL_SEGS), false);
+								  pretty_wal_size(DEFAULT_MAX_WAL_SEGS),
+								  false, false);
 
 	/*
 	 * Fix up various entries to match the true compile-time defaults.  Since
 	 * these are indeed defaults, keep the postgresql.conf lines commented.
 	 */
 	conflines = replace_guc_value(conflines, "unix_socket_directories",
-								  DEFAULT_PGSOCKET_DIR, true);
+								  DEFAULT_PGSOCKET_DIR, true, false);
 
 	conflines = replace_guc_value(conflines, "port",
-								  DEF_PGPORT_STR, true);
+								  DEF_PGPORT_STR, true, false);
 
 #if DEFAULT_BACKEND_FLUSH_AFTER > 0
 	snprintf(repltok, sizeof(repltok), "%dkB",
 			 DEFAULT_BACKEND_FLUSH_AFTER * (BLCKSZ / 1024));
 	conflines = replace_guc_value(conflines, "backend_flush_after",
-								  repltok, true);
+								  repltok, true, false);
 #endif
 
 #if DEFAULT_BGWRITER_FLUSH_AFTER > 0
 	snprintf(repltok, sizeof(repltok), "%dkB",
 			 DEFAULT_BGWRITER_FLUSH_AFTER * (BLCKSZ / 1024));
 	conflines = replace_guc_value(conflines, "bgwriter_flush_after",
-								  repltok, true);
+								  repltok, true, false);
 #endif
 
 #if DEFAULT_CHECKPOINT_FLUSH_AFTER > 0
 	snprintf(repltok, sizeof(repltok), "%dkB",
 			 DEFAULT_CHECKPOINT_FLUSH_AFTER * (BLCKSZ / 1024));
 	conflines = replace_guc_value(conflines, "checkpoint_flush_after",
-								  repltok, true);
+								  repltok, true, false);
 #endif
 
 #ifndef USE_PREFETCH
 	conflines = replace_guc_value(conflines, "effective_io_concurrency",
-								  "0", true);
+								  "0", true, false);
 #endif
 
 #ifdef WIN32
 	conflines = replace_guc_value(conflines, "update_process_title",
-								  "off", true);
+								  "off", true, false);
 #endif
 
 	/*
@@ -1336,7 +1332,7 @@ setup_config(void)
 		 strcmp(authmethodlocal, "scram-sha-256") != 0))
 	{
 		conflines = replace_guc_value(conflines, "password_encryption",
-									  "md5", false);
+									  "md5", false, false);
 	}
 
 	/*
@@ -1348,7 +1344,7 @@ setup_config(void)
 	if (pg_dir_create_mode == PG_DIR_MODE_GROUP)
 	{
 		conflines = replace_guc_value(conflines, "log_file_mode",
-									  "0640", false);
+									  "0640", false, false);
 	}
 
 	/*
@@ -1359,7 +1355,7 @@ setup_config(void)
 		 gnames = gnames->next, gvalues = gvalues->next)
 	{
 		conflines = replace_guc_value(conflines, gnames->str,
-									  gvalues->str, false);
+									  gvalues->str, false, false);
 	}
 
 	/* ... and write out the finished postgresql.conf file */