I've been playing around a bit with my pistols, and it seems that all of my 3rd generation slides and frames will swap around with no problem, and same with 2nd generation pistols. All 9mm by the way.
However, when I try to put a 3rd generation slide on a 2nd generation frame, it seems like it should go. After about 1cm, the slide meets resistance as if the frame rails are a different dimension. I certainly don't want to force anything, so that's as far as I have gotten.
What is the point you are asking yourself? I have a slide and barrel from a 3914 with all of the 3rd generation advantages, and I'd like to put it on my 469 frame. I've seen hybrids like this in the past, and I'd like to know how they are done.
I'd rather not make any modifications to the frame, in case this doesn't work out. I'd hate to ruin a perfectly good pistol.
However, I think it would be cool to have Novaks and the improved safety lever on my 469.