[Dovecot] Is dovecot locking properly?

Hello, I'm attempting to move form qpopper 4.1 to Dovecot 2.2.5 on Linux. When a user checks POP mail qpopper seems to make a .username.pop temporary file in the same /var/mail directory as the mbox INBOX file. Watching what dovecot does I don't see this happening.

Is this .pop file a lock file or just a temporary file? If its a temp file does dovecot do the same thing elsewhere? I'm concerned dovecot is not locking properly and there will be mailbox corruption, so I'm trying to get dovecot to mimic what qpopper does as much as possible.

I'm using procmail and its Locking strategies are: dotlocking, fcntl(), lockf(), flock(). I'm using sendmail too. I left dovecot's locking as the defaults.

Thanks for any tips.