In the streets on the eve of the Communist takeover (1948), Dieyi and Xiaolou watch the chaos unfold while seen between them in the background is Master Zhang the Eunuch. The next shot reveals Master Zhang sitting across the street from them.
When Douzi is first examined by the owner of the opera troupe, his extra finger is on his right hand below the thumb. When he withdraws the hand from the opera troupe owner, he pulls back his left arm. When his mother cuts the extra finger off a few moments later, it is now on his left hand, next to his pinkie.