NP231 input shaft questions

My jeep is a 21 spline input 231 and the bearings are shot, I bought another 231 that has the A.A sye kit. The problem is the one I got is a 23 spline input. My question is......
If I take the 21 spline input shaft/planetary gear assy out of the t-case in my jeep and put it in the case that has the 23 spline input will it work?
There both from 96 cherokees.

yes it will work. and definatley swap the entire planetary assembly rather than just the input. replace the case seals while you have it apart too.