This is a true story.
An acquaintance of mine purchased a rust-bucket 340 cuda from back east. It was heavily optioned with two fender tags. Other than the hood, there literally is not a single body panel on this car saveable. Floors, trunk floor, deck lid, doors, quarters, cowl, frame rails- all were either rusted away or needed replaced. Call this car A. He also owned car B, a plain jane 318 car of the same year. So, you can guess what he did. Car B now sports car A's docs. This brings up a few questions. First, how much of a car can you replace until it ceases to become the car it was? Would you call a car "the real deal" when the only original parts remaining on the car were the core support and cowl? Should he have let car A die? Would you have?
He could have spent the additional thousands and thousands of dollars and transplanted the non-rusted car B stuff to car A. Would you bother doing that? He does not buy and sell cars- this one is for his own use, so he is not out to defraud anyone. Someday, of course, some else will end up with this car. If you ended up with this car, would you rather have had a chopped-up vehicle with two linear miles of welded-in panels on it or the car as it now is?
I'm not taking a position here, so spare your anger and don't bust my chops over this.