The sequence where Trinita and Bambino eat at the restaurant was not written. Terence Hill and Bud Spencer created it on the set.
The "goof" where the cards were cut "improperly" was not a goof at all. It was essential to the way Trinity was able to cheat. He knew the exact order of the cards. A proper cut would have screwed the order up.
Segment from this film was used in a Oct, 2006 Sprint Broadband commercial on U.S. television. Specifically the bar scene where Terrence Hill's character is able to slap his adversary on the face, and draw his gun, before his adversary can even get his gun out of his holster.
The movie is set in 1869 according to an advertising poster on the wall in a bar.