At the beginning of the movie, when the bad guys get to town and start walking around, within a few minutes it goes from night to bright sunny day and back to night.
When Reb Carlton (Zachary Scott) is supposedly pinned to a tree by an arrow, the arrow can be seen moving with Reb's breathing, showing it was just strapped to his chest.
The stage station has a corral with an inclined stock ramp: an item that did not exist before the need to load animals on to trucks.
Abby's (Yvonne De Carlo's) hair and costume were not of the Western era.