Temple Rubbings Dale

Trying to get some info please. A friend inherited a collection of art from various places in east Asia. They were collected by his uncle who worked for the CIA. I know these are rubbings from Angkor Wat. Do you see anything unique? Since there are so many items, we grouped them into 10 lots. I put a US yard stick (3 feet or .61 meters) in the pics. Thanks!