This episode was not meant to be the final episode. It was scheduled March 28, 1969, the day former President Dwight Eisenhower died. All network programming that night was pre-empted (including the final episode of Star Trek). It was rescheduled following the originally scheduled final episode ("The Night of the Plague," April 4, 1969).
A last episode for which Jim West is really alone, no one to replace Arte character.
Last show of the series.