[CentOS] Updated Spam Assassin for CentOS 5...

I am wondering about updating the version of Spam Assassin on my CentOS 5 mail server. The current version, 3.3.1-4.el5 (stock RHEL version), has been 'leaking' recently. I suspect I need some newer match rules to detect some of the newer flavors of spam. I see that in rpmforge's extras repo is version 3.3.2-4.el5.rfx -- is this version worth installing? Are there even newer versions either available for CentOS 5 (or buildable under CentOS 5)? Or is there a collection of match rules available for the newer flavors of spam than can just be dropped into /etc/mail/spamassassin/local.cf?

I am not ready just yet to migrate my server to CentOS 6 (but that is something I'll probably do at some point).