The actual metal chassis of most later sierras were all designed to be able to be 4wd as from about 90 onwards they started to get the wider 4wd accommodating transmission tunnel so as far as bolting stuff on its all the same

What you have to remember though is that they weren't built to a perfect accuracy and so there was plenty of scope to adjust stuff around, which also explains why there are so many issues with the rear arb mounting issues when you fit a poly diff mount

There were also a different length threaded and shouldered arb available so it really is a whole losd of tiral wnd error to fit stuff on in the correct place