Hecky makes reference to James Cagney and says, "Made it Ma, top of the world." But this scene takes place in 1947 and Cagney said that line in White Heat (1949), which was released in 1949.
Although the time is established as 1947, a character talks about Kodak Tri-X film, which wasn't introduced until 1954, and then shows the negatives, clearly marked as Tri-X 400, which wasn't introduced until 1960.