Museum, maybe? But, they aren't about to sell them. They would be part of the liability chain on a car that didn't meet US DOT safety standards from the manufacturer.
You buy the car, change back something that was changed to meet the DOT standards, you get hurt. You sue because you didn't know any better, and that is how the car was originally built.
You win millions and millions of dollars, and they made 40,000 on the cars. This tells you what they really think of gray cars from their perspective.