His car his choice. If it has the VIN and is registered as 3097 it's still 3097. The value is totally in the hands of the next buyer. If he's a Shelby purist he'll base his offer on what it will cost him to put the car back to stock. If it's a nostalgia buyer looking to buy the car he wanted in his youth he may actually pay far above "stock" GT500 prices. Watch Resto Mods at the auctions if well done they pull more money than very nice stockers.