My guess is that the person who was stamping the engine and trans forgot to change the VIN# prior to striking it, realized the mistake, corrected the VIN#, and then heavily struck it to cover up the mistake.
Hmmmmmmmmmmm "What if" there is another trans with the numbers restamped on this trans with them under the numbers that you can't read A simple assembly line oops that someone caught. Two 4-speed transmissions attached to the wrong engine and caught by quality control. Instead of taking everything apart it's just so much easier to re-stamp both and keep the line moving.
Remember production was about a 1,000 cars a day back then and do you really think that they cared if 40-years later someone would say "oh for sure that's a non-factory restamp there because someone made a 4-speed out of an automatic to increase the value"
What would you do if you were the production manager and someone pointed out the assembly error with everything already bolted together?
I agree with the fact that the original numbers are still there and the re-stamped numbers are pretty darn straight to not have been done with a multi-stamp fixture like used on some assembly lines.
Hmmmmmmmmmmm "What if" there is another trans with the numbers restamped on this trans with them under the numbers that you can't read 
A simple assembly line oops that someone caught. Two 4-speed transmissions attached to the wrong engine and caught by quality control. Instead of taking everything apart it's just so much easier to re-stamp both and keep the line moving.
