A large part of it is salesmanship. I have the original block for the Bud Gates '67 Z-28 race car which is also one of the first 25 Z-28s built so it is not the only early block in existence. Gary Morgan still had the original block in his possession but was asked if he would loan it out to the then current owner who wanted to display it with the car at a show (I forget which show off the top of my head). It was only on loan and yet was never returned to Gary. As you can imagine, Gary is still pretty upset about it. It might be the only very early block displayed to the public other than when the cars were new but is not the only one in existence. There is another very early block that exists but we are not certain yet if it belongs to one of the first 25 cars. By the way, these first 25 cars were not prototypes, nor pre-production. They should just be considered early production and that's it.