Tom's distinctive machine gun is a Lewis gun. It was designed in the United States, but was primarily used by British forces in WW1 and WW2. It weighed 28 pounds (13 kg) and it's pan magazine on top could hold up to 97 rounds. The barrel is surrounded by a cooling shroud encasing aluminum fins that act as a heat sink. The allows Tom to fire the gun without burning his hand.
In life, Villa helped fashion his own image as an internationally known revolutionary hero, starring as himself in Hollywood films and giving interviews to foreign journalists.
According to a contemporary article in Daily Variety, Van Johnson had been cast in the lead role of Tom Bryan.
Gilbert Roland and Joseph Calleia (Pablo) both appeared previously in Juarez (1939) and Underwater! (1955).
Shelley Winters confessed that this film was the most fun in which she ever played.