In this case there isn't any altering of the VIN as the VIN stamped into the body / frame is the official one. ( Re: He isn't taking the VIN from car A and placing it on car B. )

I'm not sure what the laws are pertaining to the public VIN ( visible through the windshield ) Some cars have a vin tag / sticker on the door integrated into the vehicle information data plate. When the door is changed I usually don't see a replacement sticker. Same goes for VIN coded parts such as hoods, fenders, doors and bumpers.

Did similar year Euro market cars have a public VIN?

I doubt that black helicopters are going to show up on your door step, the current administration hasn't reached "Minority Report" levels as of now.