[Tinker51]

My car had a vin tag with the SPF # as the vin. The vin tag was the "AC CARS" one from cobra accesories and was rivited on by the guy I bought the car from. The CHP officer I had was really only interested that the number on the paperwork was the same as the one on the car. I got the impression that the actual number is not important only that it is permanently attached (more or less) to the car. So I say to you, come up with a good number (a manufacturers number will do) have it engraved on a data plate and rivet it to the car. I guess you could take the engraved tag and a rivet gun with you.