WAL files during a backup

I have a question regarding the WAL files that are moved during a backup to the "archive directory".

I have setup the postgresql.conf file to have the following archive command:

archive_command = 'cp -i %p /var/lib/pgsql/backups/%f </dev/null'

Environment:
PG Version 8.1.4
OS: Linux 2.6.18-8.el5

After I have run the pg_hotbackup script, the backups directory contains only 2 files:
1. The gzipped tar file pg_hotbackup_<timestamp>.tar.gz, and
2. a WAL file ".backup" file, (for example 00000001000000000000223387.0089ED8C.backup)

The actual WAL file did not get copied to the backups directory. From the example above, I would have expected at least 1 WAL file named 00000001000000000000223387 to be in the backups directory.

My questions are:
1. Is this normal behavior? (perhaps no activity in the DB to cause a WAL file write during the backup?)
2. If I try to restore the DB without this WAL file, will the restore fail?

Thanks in advance

Drew