Where to find date codes, etc. on 12 bolt diff - 1969 Z28

[JST69Z28]

Where I can find the date codes and any other stampings on the 12 bolt differential on my 1969 Z28?  The diff has been undercoated and painted several times before I got it, and I want to know where to clean to find the numbers.  Attached is a photo showing some numbers I found on the right rear next to the diff cover.  Thanks for any help.

[cook_dw]

http://camaros.org/drivetrain.shtml#axle

[JST69Z28]

Wow, great info, thank you.