I agree the *should*, but IME very often they don't. Even when you do GW afterwards - which is what we do here (base image has office 2k on it, GW is an add-on) It may work for a bit, but sooner or later it seems there are profile-related issues over who the dflt email program is, whose address book is going to be used etc. We took removed outlook from our office install (among other items) and cut support calls a ton. I have 2 users who have to have outlook for their address books and those two have the highest # of support calls in the entire company, bar none. I hope GW 7 (or whatever they call it) will finally nail the PIM piece of the program.
Anyhow, fwiw I am almost certain that the problem ChipsAhoy is having is bc Groupwise is not the default email program in the registry. I have seen this happen before.