Differences in 350 Rancher shift drums

I have a 2000 Rancher that ran, and a 2002 for parts that seems to be locked up.

Both are going to be torn all the way down. Is there a big improvement in the 2002 shift drum? I’ve noticed the 2000 is a one year only part and the 01-06 all used a different drum.

I’m going to tear the motors all the way down and depending on what I find I might just rebuild the 02 motor, or if it’s in bad shape inside, swap the 02 shift drum over to the 00 motor IF there is a design problem with the 2000 Ranchers.

Plan is to split cases, check the crank, clean everything well, install a fooftshift spindle (it’s an ES currently), put in new seals, new timing chain, and new top end. Just not sure if I should just rebuild the 2000 engine or if I should try to rebuild the 02 or possibly take parts off of the 02 and swap onto the 00 if there was a design improvement.

Anyone tell me what I’m looking at here?