VIN matching 68 cuda

I do think there could be some other explanation other then theft. What you are missing, as pointed out, is the real VIN. At some point somebody who didn't know how pre 69 Mopars work made this extra tag that matched the body stampings, then they took the car to the police and had it inspected where another person unfamilar with the way a 1968 VIN should look signed off on that being the car and that there is no record of that number being stolen (which of course not because they never got that high in 1968 barracuda production). Then with the police signed off they went and put in for a lost title and that wrong number was assigned to the title.

Now the real question is why they replaced the VIN and what is the real VIN of the car. It could have suffered something like an interior fire in it's life, and whoever restored the interior was unfamiliar with 68s. The VIN tag could have been stolen to be used on another car where the whole car was stolen. It's even possible somebody purposely did this thinking the VIN was supposed to match the other stampings. Of course the most likely is that it was stolen in some form or another weather just with a lean or a divorce or improperly handled estate or outright stolen!

The first think I would do is start searching for a build sheet, if you can find that then you can see what real VIN is.