log_min_duration question

From the 9.5 docs:

log_min_duration_statement (integer)

Causes the duration of each completed statement to be logged if the
statement ran for at least the specified number of
milliseconds. Setting this to zero prints all statement
durations. Minus-one (the default) disables logging statement
durations. For example, if you set it to 250ms then all SQL statements
that run 250ms or longer will be logged.

While the first sentence explicitly states a fixed unit (namely msec),
the last sentence seems to imply a (maybe optional) unit suffix
(ms in this case). Which one is true?

How would e.g. "SET log_min_duration_statement=1min" be interpreted?

I'd prefer a docs clarification.