reax axel

Looking to upgrade rear axel shafts. 2004 Rubi, geared to 5.13, stock F&R lockers, on 35's. If I've read correctly, splines need to match lockers and spider gears? Stock rubicon is 30 spline, so if I have stock lockers is it safe to assume the shafts that are in are currently 30 spline? I'm 2nd...