I don't think it "tells which car", but I agree that is the build tag for the seat. Identical seats (shape, location, material, date assembled) would have identical tags. What I have observed is that the seats were marked by hand with the vehicle rotation number for quick and easy association with the right car as it went down the assembly line. I've seen this same practice on other components including door panels, instrument clusters, and fuse panels.AFAIK It's the build tag for your seat. It tells which car, what color, and style as ordered on the build sheet.