I've done it; the only real issue I ran into is the newer door shells (95-up) have an indentation where the inner door module (or "door card" as some call it) attaches, IIRC it's a slight bit of clearance for where the inside door handle slides in. You could simply force the handle gently or get creative with a hammer, vise grips, etc. bend the skin a tiny bit. The difference in the shell itself is not significant.
You may run into trouble with the outside door handle as it may not fit properly. I've debated this to no end with a few people but the fact is the newer door shells have a slightly larger door handle opening and the newer handles made up for it by having a thicker plastic surround "gasket" which is attached to the handle, so, be aware of that.
I'll also add that I've had the best luck door swapping as close to year model as possible, in terms of overall fit. I'm no body man but I'm decent at adjusting doors on GMT400's; sometimes if you get too many years apart in doors they just don't fit right no matter how hard you fight them. YMMV
Richard