VIN Code Question
Just like on a Chevy the VIN (or partial vin) will be stamped on the block and transmission.
The 9-71 is most likely the build month and year. Nothing strange here, model year starts before the actual year (72s hit the showroom floor around September of 71).
Not sure where the vin is stamped on a 72 block, I think it's around the oil pan rail.