At one point, Cora Dufrayne (Telford's girlfriend) is trying to seduce gunslinging anti-hero Reb Kittridge. And, when he mentions having been driven out of Arizona, New Mexico, and Wyoming, she replies: "You're running out of states." Wyoming, however, did not gain statehood until 1890. While Arizona and New Mexico remained territories until 1912.
When Audie Murphy tells Jesse White to turn his chuck wagon around to avoid the grass fire, a pair of arms can clearly be seen behind White and in the back of the wagon, holding the real reins to the horse team.