I am trying to verify that a 12 bolt I bought came out of a 69 Camaro. It has the numbers 388488ONF & GM57 on the housing. Do these tell you anything?

One is the casting number. The number should be 3894860NF and is the correct casting for 67-69 12 bolt. The GM 57 means nothing. There should also be a casting date on the pumpkin on the drivers side rear top.


Here's some reading for you that will help you locate these codes:

http://www.camaros.org/numbers.shtml#RearAxleNumbers

See if you can find a stamping on the forward part of the axle tube