3.23 7 1/4

Wheres the Codes on the rear end housings for these? Am more of a GM specialist, GM often/usually put the codes on the R (passenger tube) facing forwards towards the front of the car.
Two donor cars in W side El Paso pick a part currently. Both are slanty three on the tree stick cars. Am guessing most likely both are 2.76's? They're getting pretty picked clean by this point, but rear ends are still in both...

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