Dumb part interchange question time

[Critter]

I know these questions have been answered somewhere before, but after searching I couldn’t find the sort of detailed answers I was looking for. The 76 GMC in my signature may begin to get a facelift. It is in pretty good mechanical shape but the body is in need of some help. I think I have access to some FREE 81-87 parts trucks. Will the doors and bed from the 81-87 bolt up with no issues? I know there are some differences in the doors 73-76, 77-80, and 81-87 but aren’t they all purely cosmetic and related to the door panels? By the way, I would change them out as a set, of course. Same for the bed, I know that the fuel filler changed to a door/doors in 78 (or so???) but other than that it would bolt up just fine, right?

Sorry for my ignorance, but I have been pretty submersed in the 67-72s for the last 6 years or so and have forgotten a lot of the details about the 73-87s.

[Prong]

77-87 (up to 91 burb and blazer) doors are the same. The panels run from 77-80 and 81-87. You can interchange the panels as a set between doors. You'll also have to use the matching inner door handles/cups that match the panel years. Beds should bolt up--if you're going from outside filler neck to doors, you need the filler neck, hoses and gas cap from the newer donor truck, because they're different.