He is! Wu Xie is called an 'iron chopstick' in that he is more of a historian than actual thief, though he is very hands on about his history study.

He could do that because he guesses about the stuff he sees in the tombs but he doesn't know. His family is also big in the collecting, cataloguing and conservation of relics too. (Though at one point in time they were infamous thieves and murderers with viciously trained dog packs.)