That's Typical of what I have seen & heard of Service replacement Transmissions.
There were 4 Transmission plants making these,and for the following Car Manufacturers:
Buick-Olds-Pontiac-Chevrolet-Cadillac.They didn't use a Pass. side suffix tag,because they didn't know what application that trans. would be used for.
Your findings help back that up.
I Thank You.
Rick