Matching #'s question

[drdave69]

The VIN derivative will be stamped near the code you mentioned. It will be something similar to '9NXXXXXX' where the Xs are the last 6 digits of the car's VIN. If there isn't a VIN stamped on the trans case, who knows where the trans came from? It does appear to be a 1971 assembled M22.
One of the best reference books on the market is Jerry MacNeish's '1969 Z/28 and SS396 Fact Book'. Pick it up and read it (over and over in my case). You'll learn quite a lot about your car thru it.
check your trans case again for another set of stamped numbers and let us know what you find.
Dave