that i dont know, i'm guessing they are physically identical with the only difference being the axles are slightly longer. Maybe mike knows a way to distinguish them apart besides lenth.
are you needing some stock axle shafts or a whole rear end?? if all you need is some stock shafts i have 2 sitting in the garage taht i took out when i did my 31 splines. let me know if you need them.