DMVs have a book of manufacturers - but never seem read it. The MSO that went with the cars clearly stated manufacturer (65-67 Shelby American - 68-70 Shelby Automotive). But I've seen Shelby, Ford and Cobra listed. My own Hertz car said GT350 for make. Before 1968 builders selected their own VIN designation. The National Highway Act (1968) designated the 17 digit VIN we use today and where it should be located. Go to DMV well armed - these things were built long before the DMV clerk was probably born and they have not encountered one before. If you get some officious idiot who knows everything you will need to educate them that it is not a Ford Mustang but a Mustang GT-350 manufactured by Shelby American as clearly shown on the VIN plate and the second matching VIN stamped on the passenger side. The Ford VIN should not even enter into the conversation. Keep going up the food chain and eventually you'll find some old guy that says - oh yeah I remember these.
On the other hand hopefully you'll get the typical lazy state worker that just rubber stamps whatever is put in front of them.
On the other hand hopefully you'll get the typical lazy state worker that just rubber stamps whatever is put in front of them.