While the diff is an 8.8 which is the same on 4x4 trucks, the pinion has 31 spines (as opposed to 28) and it is a little more robust than the ones on our trucks (especially the 4x2s with their 7.5 diffs). And disc brakes have more stopping power--something you'd probably be happy for if you are towing or carrying a heavy load. = And most of them come with a limited slip, which is a definite plus if you don't have one already. The track is an inch or so wider on each side.
Try to get the e-brake cables too and the springs and it'll be easier to install. you can use your springs, but you'd have to weld perches on the top of the axle (exploder springs are under the axles).