James - Thanks for posting those. The first pictures is the units casting date code: D273, which decodes as April 27th, 1973 (or could be '83). The GM14 is just a standard GM foundry marking/number which doesn't provide any real detail about the axle. The 3rd picture with "1235542B" is a casting number for the main case, but doesn't really identify the axle to see what it came from.
The key alpha/numeric info needed is stamped into (not cast) the upper face (close to the differential pumpkin) of the passenger side axle tube. Below is a sample of where and what to look for. Those are the codes that will tell what the axle original was installed in as well as original gearing etc.
You've got the picture taking/posting process down, just need to see the stampings on the axle tube and we can go forward from there.
