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.
As the Younger gang enters town, and goes by the College, there are modern day picnic tables clearly visible as they ride by the building.
On their way to Northfield, just outside of town, Jesse's gang is riding on paved concrete and asphalt roads, which did not appear until the mid 1920's.
During the baseball game, when the player picks up the shot baseball cover, in the upper right corner of the screen, a modern car can be seen moving down a road in the distance.
The film is set in 1876 yet Cole Younger carries a model 1892 Winchester rifle.
When the Younger gang arrives in Northfield, there are automobile tire tracks clearly visible in the muddy street.
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).