Some 88's with the tow package and transmission cooler came with a Dana 44. But mine didn't. But 87's came with the dana 44 with the towing package. Probably because the 88's were the last year for AMC production. My 88 now has a dana 44 rear differential out of a 87.
Most 87 XJ's with towing package had the Dana 44. I have an 88 XJ with towing package but had a Dana 35 which was junk from the factory. It now has the Dana 44.