POLICY SERVER --> PSTORE
Point new policy servers to existing pstore.
Update cert8.db for backend SSL Connections.
WebAgent --> POLICY SERVER.
Update Host Configuration Object in WAMUI.
Update SmHost.conf for boot strap (optional) in SPS.
Since your Policy Server version is CR02 and CR04. Only Install the Policy Server binaries on the new servers.
I would compare XDD files across both versions before running XPSDDInstall, just to make sure I know if it absolutely necessary to run XPSDDInstall.
Similarly I'd also compare smpolicy.xml, ampolicy.xml and all the other xml files which import default object - across both version - to be absolutely sure if I need to run'em because of any new additions.
Since it is CA Directory, I'd be smart enough to backup the policy store before I begin running any XPS Commands.