First off, you don't have to capitalize or use punctuation, but if you write in all lower case instead of all caps it's easier for us to read it.
Second, typically the requirement for shims is dependent on how it fits. If you get lucky and everything lines up perfect you don't need shims. More than likely you'll need shims. If you haven't done this, you might want to farm it out to a shop with experience. I personally haven't put a rearend together, but that wouldn't stop me if I had the shims handy.
If you have a G80 and the gears are for a G80, having a different carrier shouldn't make a difference. The shims aren't to make up for wear, they're to make up for loose machine work at the factory. Back in the day all the machine work was loose and everything was 'adjust to fit'. In the '80s the Japanese proved that tight tolerances at the factory cost less in the long run, and everybody tightened up their standards. Our trucks are built the old-school way, thus we need shims in the rearend.