abs and 97+ shaft differences

i have 99 w/297s and my spares are from a 92w/abs. i was changing a joint and noticed that one had a larger shaft that necked down to the size of the other. dont know which is which since they have been mix and matched. I believe the 92w/abs ones are the larger ones. can anyone confirm this for me

The larger should be the 92 shaft. If you look at the yoke, it should be a yoke forging pressed on to the shaft, two pieces.

that it is, thanks