Yeah, not the same. Front uses a hub flange/bearing unit. The rear is the whole axle shaft with the hub flange made as one piece. The bearings are inside the ends of the axle housing tubes.
'91 YJ Sahara 4.0L/AX-15/NP231, D30/D35 @3.07
'12 KK Cherokee 3.7L/42RLE/MP1522,D30Memail@example.com
Emissions testing? YES