Which Way to the OK Corral? - S2-E20
Factual error: Heyes and Curry meet Doc Holliday and Marshall Wyatt Earp in Tombstone. Wyatt, however, was never a marshall in Tombstone, though his brother Virgil was. Wyatt and Doc Holliday both left Tombstone permanently shortly after the OK Corral shootout in 1881, so wouldn't even have been there when Heyes and Curry arrived in 1883. (The year's established by Heyes reading Twain's book published in that year).
Which Way to the OK Corral? - S2-E20
Continuity mistake: When Georgette tells him she plans to become a chanteuse, Curry says he doesn't know what that is. But in an earlier episode, "Journey from San Juan," he called Michelle a chanteuse with obvious knowledge of the word's meaning.
Which Way to the OK Corral? - S2-E20
Continuity mistake: At the end, Heyes and Curry tie their horses to the back of the stagecoach and get aboard. In the following shot of the coach pulling away, the tied horses are no longer there. (00:48:00)
Which Way to the OK Corral? - S2-E20
Other mistake: When Neville Brand is listed as a guest star, guest star is misspelled as "Guast Star." (00:05:08)