The falcon-shaped cannon seen in this episode was the largest prop built for the series. Although it appears to be a massive cast iron construction, in reality it was made mostly of styrofoam.
Robert Duvall, who plays "The Falcon", threatens to fire the cannon to blow up Denver, Colorado, which during the era this show is set, went from 4,759 people in 1870 to 35,629 ten years later, making it the 50th largest city in the United States. Lisa Gaye (Lana Benson) was born in Denver.
When Gordon is doing research, he picks up a 3-ring notebook binder. The 3-ring binder was invented in 1886 in Germany. It also appears to be the vinyl covering which did not appear until around the1940s.
The town blown up in the opening is called Tonka Flats. The mother of the child saved by James West in the opening tells the Army they are being treated like windup toys. Tonka is an American company that has produced children's toys for many years.