'68 GMC rear leaf width questions

[68chevyfuelie]

I am hoping someone has a '68 C10, rear leaf, 2wd, and wouldn't mind measuring the leaf spring pads, center to center.

I come up with 42 1/2", center to center. I have 2 4wd 12 bolts, the '69-72 style, that measure 40 1/2" center/center. The '73-81 style 12 bolts 2wd seem to be 42 1/2" as well. Am I correct in assuming 4wd 12 bolts are different than the 2wds?

I was told my truck originally had a Dana 44 tucked back there from the factory. Can anybody tell me if trucks that came with the Dana 44 had a different leaf width than trucks that came with a 12 bolt?

Thanks all!!