12 bolt info needed

[xs-cash]

I have a 72 Cheyenne with a 12 bolt with leafs , factory set up , I’m wondering if the rear end from a 73 and up is the same overall dimensions? Or are the 67-72 halfton with factory leafs are different? Can I bolt in a 73 and up 12 bolt halfton rear end into my factory 72 leaf spring truck ? Or are the mounts and spring perches different?

[gmc684x4]

It should bolt right in measure the spring perchs on both diffs
The wider 70-72 diff axles are the same as the 73 up 12 bolt the 67 69 diffs are a bit narrower