The film was shot mostly in Jacksonville, Oregon, whose landscape bears little resemblance to that of Northfield. Many errors result from this, such as the hills outside of town (Northfield is located in relatively flat farm country).
The character of Jim Younger played by Luke Askew is shown prior to the Northfield raid with a mouth deformity that he attempts to hide or disguise throughout the movie. He obtained the injury (gun shot) to his mouth during the raid. The error may have been caused by most of the historical photos of Jim Younger are from after the raid and his arrest showing the injured upper lip.