Help please ID'ing my just bought rear

[67gmcstepside]

I am trying to identify exactly what I bought. The PO wasn't sure if its a 70 -72 but sure it came from a blazer. Its a 12 bolt, 6 lug and it looks like a posi.



On the back lower side of the rear, facing back is a date code of C292 which I am assuming is MArch 22 1972. The stamping on the axle tube is:

The stamping on the axle tube is: RA Z W094 2 E

How can I tell what gear ratio it is. On the ring gear is stamped 381779 14 :43 and GM 3 72 2

As always THANKS!!