I can do a yum update in my post kickstart (which is what I am doing now actually).
Maybe a better way to do this...
However, I want to save network time at installations. If I copy down the files from centos/5.3/updates/x86_64/RPMS and place them in a directory local on my network, can I just "rpm -U /mnt/directory/updates/x86_64/RPMS*" in my post section?
If that is the case, then add a repo line in your kickstart, sync an updates repo as you do, it will pull anything it needs that is newer from this repo line.
repo --name=Updates --baseurl=http://foo.example.com/pub/centos/5.3/updates/i386/
Works for me (tm). jlc