Revealing mistake: Jack Albertson's character is taking pictures of The Cartwrights and ranch hands. The video camera moves across the front of the prop camera as Albertson pushes and holds the button to take a picture. The shutter on the camera never opens and isn't open until he releases the button. In those days the shutter had to stay open an elongated time to enable the light to infiltrate the negative. People had to stay still during this time.
Continuity mistake: The schoolhouse has two windows, one on either side of the door. From inside, the view out the windows is of a grove of pine trees. This is obviously a painted backdrop. When the students exit the schoolroom, the nearest tree is a large white-limbed tree with no leaves.
Revealing mistake: Joe and Eddie are in a corral in a big valley, taking turns trying to tame a horse known as Hammerhead. In the long shots, obviously using stunt doubles atop the horse, Hammerhead is bucking and running. The close-ups of Joe and Eddie show them only from the waist up and they are not moving forward. They are simply bouncing up and down. In addition, the close-ups show only blue sky and not the surrounding hills.