If you're going to restore a car to that level then its going to places like Pebble Beach. There are Concourse de Elegance shows all over the country. Most times you see European sports cars like Ferraris, and brass era cars, but many times there are muscle cars at these shows as well. BTW, a 100 point restoration on a Ferrari will have the assembly line markings added back too.

I'm not agreeing with adding the markings, I just understand why some people do it. Yes its not "original" since its only original once but...with the markings added a restored car will be as close to factory original as humanly possible.