Typically, ANY markings of that sort (CertiCard, owner's manual, etc.) were done at the dealership by their people. Some dealers removed the owner's manual packet and put them in a file, matching them up with sold units at point of sale. Keeping track of CertiCards could be similar. The CertiCard owner information was put on at the dealership when new or when the car was re-sold at the dealer's used car lot and transfer the 5/50 warranty to the second owner. One of the first industrial uses of the Dymo Label Maker?
The rear view mirror seems a little extreme, as to what it took to do that, but safe. When the VIN plates were at the base of the windshield, much of that became not-needed.
A dealer's "stock number" could be the last section of the VIN or a self-generated number, at their discretion. Something to reference the vehicle to the appropriate "vehicle folder" in the filing system.
Many dealers would remove and store the spare tires from pickups, if they were in an area where they were prone to be stolen. Many took the chance, not desiring to go through what it took to keep up with them in the parts room.
CBODY67