That is the first time I have heard that. I only know that the carrier assembly for 2.45 is specific due to it's size. It was my understanding the housings were all the same.
My bigger concern is the late model carrier. Mopar Action says it can be used with stock length axles, they just need to be cut with the late model spline pattern. I am currently double checking my research to make sure this is true so that I don't order a set of useless axles. I am going to put up a specific question thread regarding 27 vs 29 spline.