When the Judge gags McCain with a bandanna, only the solid-colored part of the cloth is visible across McCain's mouth. Later, just before McCain manages to free himself, the white-design part of the cloth is now visible across his mouth.
When Lucas McCain (Chuck Connors) is at his ranch unloading wood posts from his wagon and Marshal Micah Torrance (Paul Fix) rides up, the sweat stains on Lucas' shirt appear and disappear and move around between shots.
The letter sent to Lucas MCain, when shown in the hands of Mark, has a modern stamp and postmark from 1958, the year this episode was released. The story is placed in the 1880s.
Judge Burton shows up at the McCain ranch and pulls a gun on Lucas. He's using a single action pistol with the hammer down and it must first be cocked to fire it. His thumb is nowhere near the hammer and it's doubtful anyone would hold a person at gunpoint like this.
When Lucas thought that Judge Burton had shot Mark and grabs the Judge, Mark emerges from behind the rock and tells Lucas it was a rattler while holding a snake. However, the snake had a pointed tail with no rattles on it.