When my Puma was brought into the country, a 1965 VW Bug gave it's life and VIN numbers. It's titled as a 65 VW. Low insurance, no emissions testing. Perhaps you could find someone with a title and the numbers neaqr the transmission inspection plate to do the same.
Depends on what state your are located in and what year you want your Puma to be. As Jim mentioned, you can title it as an old VW "Kit" car or try to source a pre-73' USA Puma title. I have an 85' GTI that was titled in AZ back in 87' as a "REPLI" "PUMA". So my factory Puma is titled as a replica of a Puma. Go figure. I have to conform to all the emissions standards for 1987 though.