Exactly. Nope, having a previous beta and applying the combo update only replaces the similar files with new ones, it doesnt replace the extra files from the 10.6.5 beta. It is a set of 3 files that enable AirPrint computer side.
I didn't install 10.6.5 beta, AirPrint wasn't working. Got the 3 files, and AirPrint started working
