[Dovecot] How Can I Tell How Dovecot Was Installed?

[Blake Carver]

I'm trying to help someone with Dovecot, and it looks like this one is
a few versions behind.

They say that they're not sure if it was installed Via an RPM or a
source tarball. Dovecot is use MySQL.

This is a RHEL5 server. There are RPMs listed as installed (rpm -qa)
but I don't know how I can tell what was used to install the currently
used set up. (also asking on the Postifix list)

Is there something in a conf file or something that shows me how it
was installed?

Thanks
Blake