Trans ID and Date
 

I have a 63 gmc and after some initial research it appears that when the small block chevy was swapped in they also swapped in an sm465 and maybe a different rear end.

For the transmission, see the attached pic. Want to confirm this is an sm465 and would like to figure out how to nail down the manufacture date.

Stamp ID:
465452
9312

I believe the 465452 points to a sm465. The date code 9312 might refer to 9 month but then 31 wouldnt be the day of the month because september doesnt have 31 days. Finally the 2 might be 72? 82? Thanks for any help.