Howdy fellas, first post here. Hoping you can help. I have a 1988 Chevy Cheyenne 2wd. I need the fenders, the doors, and the short bed. Are there any other years that have the same body panels? I keep getting told that this is an odd ball year. Thanks
Like the others said, for the *most part* you can get parts from any year GMT400 - more or less. The bed, 100% the same, no worries there. (edit: your '88 tailgate uses the link style supports instead of cables, so if you're re-using your tailgate on a bed that has a cable style support on the tailgate, you'll just need to move your attaching hardware over - no big deal at all)
The fenders, very little worry. They're pretty much the same from 88-94, and in 95-up they are still essentially the same but have some additional holes stamped on the inner wall for mounting the newer variations of 4WAL module bracket, PCM bracket, electrical center, etc. all the changes that came with 95 and then 96-up. They'll still work for your truck.
Doors are a special subject for several reasons. As fancyTBI said about the tooling, the doors are more of an issue of fit, especially since the hinge halves are welded to the door shell and to the cab so there's no easy adjustment. The closer you can get to your year of truck for the donor, generally the easier time you'll have fitting the doors. Go too far apart and it can be nearly impossible to "adjust" (read: BEND the door shell) to make it fit correctly, leaving you with a door that's hard to close, rattles, leaks wind/water at the weatherstrip, etc.
Then more on the doors, 95-up have very different interior panels, which have a corresponding difference in the door module - which is what GM calls the sheetmetal piece that bolts into the door shell that carries your window regulator mechanism, switches, inner door handle, etc. You can use your 88-94 style door module in the 95-up door. Also, people with 95-up trucks can use the older 88-94 door shells, but the top of their door module where the inner handle attaches will interfere a little with the top of the shell, requiring a gentle clearancing with a hammer.. nothing you'd ever see as it gets covered by the trim panel.
And more on the doors, somewhere around 96-ish, they enlarged the opening for the outer door handle, and they did it twice. The newer the door, the less of a chance your existing outer handle will fit correctly. GM made up for the change with a thicker plastic bezel gasket around the handle, and that attaches to the handle itself, so you can't easily just move it over.
TL;DR? bed: no problem. fenders: pretty much no problem. doors: stick as close as possible to your year model, for a whole pile of reasons.
Richard