At the tale end of the climactic action scene of the program, Floyd has just been shot, and falls from his horse, and subsequently gets dragged down the street by the horse. On the close-up shot, an obvious stunt double actually has his arm over his face, due to the fact that it's clearly not the actor Claude Akins who's being dragged.
The door of the bank safe has no locking bolts or any kind of latch at all, revealing it to be a prop and not a real safe.
Hattie tells Mark he has raised a fine sow, then asks how much he wants for him. Sows are female pigs.
Carborundum is a compound of silicon and carbon. It does occur naturally but is extremely rare. It wasn't synthesized until the 1890's, and its primary use has been as an abrasive. It has played a big part in electronics; first being used to make detectors in early radios. Much later it started being used in solid state electronics; such as LEDs. It wasn't until the 1980's that it began being used as part of the compound that makes up Chobham Armor (used in the armor of M-1A3 Abram's Tank. It's also used in the "chicken plates" in modern military bullet proof vests. It would not have been possible for it to have been made into a safe in the 1870's.