Several years ago, before I owned my Challenger, I went to Garlits show in Ocala (not in hawaii, 4c) and saw a vendor selling "old" vintage tags. I thought it was for novelty, untill I saw one on a 74 Cuda! I stopped him and got the name of the guy where he purchased it.
I had to buy the tag ($50) from him (i picked my own tag from what he had in stock) and send it to tallahassee to have the tag checked and then they sent it back. Its a 1971 vintage tag.
The second year I had it, the state tried to "replace" the tag (Florida tags get replaced every 5 years). I had to go to the tag office and show my arse!!
Its been 8 years now, its only the price of a regular tag and it never gets replaced, but you cant transfer it to any other vehicle unless that vehicle is a 1971!