Character mistake: Season 4, Ep. 29, "Bald-faced Boy": Uncle Del forgets his nephew's name during the argument in the cabin. He calls Brett "Mike," which is neither the actor's name nor that of any of Del's other relatives. (01:11:00)
Deadeye Dick - S5-E9
Character mistake: Bob's father's name is Harry Foley according to Granger and the end credits. But James Drury apparently forgot this in one scene, where the Virginian addresses Harry as "Tom."
Character mistake: Set decorator failed English 101 here. The sign over the cemetery gate is misspelled "cemetary."