Jimmy barging in, listing cons
When Jimmy is yelling at Chuck after having barged in, he is spewing a bunch of con game names (sorry, wish I'd written them down and I refuse to go to imdb to see if someone had posted them in trivia). This tells me that Chuck is well aware of cons -- maybe he and Jimmy pulled off a few when they were kids? Maybe he was the one who taught them to Jimmy? -- and in fact Chuck may turn out to be/have been the bigger con man among the brothers.