This is not really a Wagon Train story. The only two regulars are Coop and Hawks, and they appear for less than a minute at the beginning of the show. The rest is a story told in flashback that Coop tells Hawks about the Earps, the Clantons, and The Silver Lady.
Michael Burns appears as Morgan Earp, instead of his regular role, that of Barnaby West. He won't appear at all in the next episode, which is the final episode of the series.
The actor in this episode Rex Holman, who played as Ike Clanton played a few years later in an episode of Star Trek "Spectre of the Gun" as Morgan Earp.