When they are after Jubal, Rod Steiger can be seen wearing a modern wristwatch on his right wrist.
Aside from Pinky, another character in the movie, Doctor Grant played by actor Robert Burton, was also wearing a modern day wristwatch on his left wrist. The scene was when the doctor had announced that the rancher's wife was already dead and that it's all Pinky's doing.
When Jubal first walks into the ranch house to eat breakfast, between two buildings behind him you can just see the front end of a 1940s-era pickup truck. A short time later as Shep walks into the house, the truck is gone.