What year does the title show? One of the most common ways to get the later Mexican Beetles into the US was to pull an old bug out of a junk yard and "restore" it by stripping it down to the center tunnel and replacing everything else with parts from a brand new Mexican Beetle. The VIN stamped in the center tunnel would be the one on the title. There were a lot of companies doing this in the late 90s.
The one that Nick mentioned was titled as a 1998 Beetle. I don't remember the whole story on how it got here and ended up with a legal TN title, but when Hamilton County started requiring emissions testing, he ended up having to sell it. It couldn't pass emissions because it had no OBDII port. I think it passed the "sniffer" test, but they wouldn't let it pass because they couldn't plug it in. If it had been titled as a 1960s or 70s Beetle, it would have been exempt from emissions testing. That doesn't make a lot of sense to me, but you are dealing with the government here, so . . .