The log it came from may make a difference. Audit log for what?
Assuming the stuff before the dot is the epoch (seconds since 1970) then you can run this little script on it:
epoch_converter.pl
Code:
#!/usr/sbin/perl
print scalar localtime $ARGV[0];
print "\n"
Running epoch_converter.pl 1213186256 results in:
Wed Jun 11 08:10:56 2008
So if that is epoch then the message occurred today at 8:10:56 (AM).
The 20663 might be a PID.
The 105 may be an internal log sequence number.
Of course all of those guesses might be wrong - it depends a lot on what application created the log entry. Many programs do use epoch for log entries.