Latest source RPMs for 8.1.20

I'm looking for the latest source RPMs for Postgres 8.1.20 on RHEL. I
can see 8.1.19 here:

http://yum.pgsqlrpms.org/srpms/8.1/redhat/rhel-4-i386/repoview/postgresql.html

Would it be safe to say that I can download the 8.1.19 source RPM,
replace the postgresql-8.1.19.tar.bz2 tarball with the
postgresql-8.1.20.tar.bz2 tarball, update the versions in the spec file,
then build the RPM? I noticed there are other patch files installed by
the source RPM, so I didn't know if I would be missing any other
potential patch files.

Thanks.

--
Justin Pasher