Swapping parts between a '89 and '91?

I have a '91 GMC Vandura 2500. I found a '89 on offer up for cheap.Mostly just

the body. No engine or trans. I want use it to replace damaged rear left door

and a few other items. Are they interchangeable? Are the bodies the same?

From what I can tell they look like they are. Thanks for your help!