Strangely named users present

There are two users with strange names that we did not create. My coworker thinks there are temp users still hanging around from the installation. I think one is from the 3.0 GA Public release upgrade (from last Beta) and one is from the 3.0 GA Commercial release (from the 3.0 GA Public).
3v_c4nzzk and 4cef0fv4tu are the users. Is it ok to delete them? My coworke recalls they were created for testing during the install. We don't think it's used during normal operation, but we wanted to ask first.

Is it ok to delete those strange named users?
and the corollary question
What is/are/were they for?

Those users are created to enable automatic spam/ham training - the Junk/Not Junk buttons forwards mails to those users.

Ohoh, what if you deleted one?

Can you re-create him?

That's easy to fix. Just recreate the user (or create a different user) and make sure that the global config values match up:

zimbraSpamIsNotSpamAccount
zimbraSpamIsSpamAccount

(zmprov gacf will show you what they're set to - zmprov mcf zimbraSpamIsSpamAccount <accountname> to change)