You should be able to easily upgrade from RC1 to final. However we may not release any pending Errata from the upstream vendor between now and the release of CentOS 4.0 {arch} Final. Mainly depends on where we are in the rebuild, respin, prerelease testing of a given {arch} Final release.
(not speaking in an official capacity -- but based on current feedback it looks unlikely that we will have any RC2 releases.)
.dn
Thanks Donovan. Great! I'll install now RC1; get familiarized with new stuff like SELinux; wait until the Final Release; use yum to update my box; and voila! use it officially as production server!
Thanks CentOS! You're the best alternative production enterprise linux. Hope you stay forever!
str