In the movie Stand by Me, Gordie goes into his brother Denny’s room and there is a plaque of pig with the words pride, integrity, guts on it. This is with the letters pig in capitals. Is there anyway that would have been in the room at the time of the story? The scene come about nine minutes after the start of the film.
“Pig”, as a pejorative for a policeman, is found in criminal cant from the 19th century. But I don’t think it entered general colloquial Enlgish until the 1960s, and SFAIK the “pride, integrity, guts” backronym was a response to that.
The film is set in the summer of 1959. So, yeah, this looks like an anachronism to me.