How is it legal in the U. S. for private citzens/businesses to own and pedal artifacts of imense historical significance?

I saw some episodes of "Pawn Stars". In one episode, some guy sold a Roman brothel coin. Another an ancient Greek coin. One guy tried to sell what he thought was an original Raphael sketch. Another guy the gun that he thought killed Jessie James. Another a gambling kit from a famous California gambler.

I was shocked and almost cried. If I was Indiana Jones I would break into the Pawn Stars shop and steal that shit and put it in a museum. Rick himself even said once, "This should be in a museum, but it's NOT, it's in my shop."

I thought it was illegal to own, buy, sell stuff like that, as Hong Kong is the only place you can legally trade in antique artifacts.

How is it legal in the U. S. for private citzens/businesses to own and pedal artifacts of imense historical significance?
Post Opinion