I have an original 67 RS/SS car that came without the original engine as it was blown in the '70s. On the engine that I did get though, I still had the correct intake manifold, valve covers, oil fill tube and air cleaner. I pulled the car out of an old shed/barn when I bought it a couple of years ago. It had been off the streets since 1987. The car had the original 12-bolt and what was thought to be the original tranny.
We have found a correctly coded engine for it at least (MV) and when I pulled the tranny found the date stamp on the side of the tranny to be "C0R03N", indicating that the tranny was a '70 powerglide.
Others that told me that back then if a pan needed to be replaced, potentially it was just the pan off of a 70 that was replaced, meaning the tranny might be the original. Work had been done on this tranny as a manual valve body was found.
I have heard that tranny's on occasion had partial VIN from the car stamped on them. I looked at the two places where partial VINs for a 67 tranny would be (top left and bottom right) and can find nothing.
If one can say definitively where a VIN would be on a 70 tranny and it isn't on this tranny (not the date stamp, but partial VIN for the car) then I can deduce it is not a '70 tranny despite what the date stamp is on the pan.
Strengthening this logic, it has been said that some 67 trannys did not get a VIN stamp at all. Is that the same for a 70 tranny or did they come with partial VINs regardless?