Ride a Cock-Horse to Laramie Cross - S4-E23
Continuity mistake: The dye job on young Clint Howard's hair is inconsistent from scene to scene. It's dark black at the start, but pales to a shade much closer to his natural blond color in many shots later on. His brown make-up (a laughable effort to make a blue-eyed Anglo kid look Hispanic) also varies, and disappears entirely in some of the covered wagon scenes.