“1970 Dart Swinger Convertible”

I know of at least 3 others. Owner of Wildcat Auto Wrecking in Oregon had one for many years and it was pristine - looked like it rolled off the factory line. There was a blue one in the Seattle area (called Frankendart), and I saw a brown one at Carlisle in 2001. All those cars were made from 1967-69 convertibles that got hit from the rear. Big question is if this is titled as a 1970 hardtop, did they go about this the other way around (grafting earlier convertible parts onto a 70 car) or did they just use the dash VIN from a donor 70 dart?