Check out some of the threads on A bodies forum about this. The legaleze involved lets say you have a rotted to **** 70 hemi challenger. Can you swap the vin, data plate,and both the radiator upper support and left trunk weatherstrip rail to the new shell and its still a 70 hemi challenger? Or does it become a rebody, a fake, counterfeit? Can you ask as much for it as you could if you actually fixed the rust bucket you took all the I.D. numbers from? Good question. There were responses all over the map.
Personally i think and i am not a lawyer now, but i think the way the law reads everything under that vin tag can be subject to replacement. The body shell being just a "part" until it has identification numbers on it, and is assembled into a car. Some people say NO. The 50% rule applies, if more than 50% of the car is not original, then its a rebody and worth less than an original.
These same people prob wouldent give a rats *** if the vins and I.D. #s swapped over were from a rotted to **** 318 challenger with clean paperwork. The reality is, nobody in their right mind would waste the time or money to rebody a 318 challenger. Even a 340 challenger would be a stretch, because the body costs too much. Anybody doing this would be looking at using one of these for a 440, or Hemi car.
What becomes an issue is swapping vins and I.D. numbers on cars themselves, with the intent to defraud or decieve. Got a good slant 6 body, with a title lein, or its stolen, and you swap a set of numbers from a rotted 340 duster with a clean title. That becomes fraud, and is illegal. The stuff chop shops do.
However a new clean body shell does not present such problems IMHO. It should come with a certificate of origin, and is essentially just a part.
This being said slantsix, as long as you had enough of a rotted original 70 challenger with the 70 challenger vin and I.D. tags and paperwork, upon assembly you could probably run it through your motor vehicle inspection in finland as a 1970 challenger. If not, then your stuck with them issuing a VIN, prob based off your certificate of origin for the body. You may be able to get around having it have to pass for 2017 standards since you are not a low volume auto manufacturer, but a hobbiest. I am sure there are hobbiests that build kit cars in your country. Those rules could apply.