ok so.. anything from 88-98 are all the frames? even the 6lug 2500 and 8lug 2500?
Correct, as long as it's the body style of that era and 4WD, yes.
The Blazers, Suburbans and some 1 tons still used the old "square body" style up to 91 though so your 88-98 year designation doesn't totally apply that's why it best to use the body style as the designation...
Ok 88-98 1/2 tons and 88-2000 3/4 to 1 ton are the same. The 99 - 2002 1/2 tons are different. Right?
Again yes, as long as it is the body style of that era.. GM overlapped some of the model years so your better off using the body style as the application....like for example, in 2000 you could have an "old" body style 2500 (like an 88-98) or a new body style (like the 99-up 1/2 ton).