This is the second of three episodes in a row in which Chester doesn't appear. His absence is not mentioned in either episode.
Kathleen Nolan played Kate McCoy in The Real McCoys (1957). After a real-life horse riding accident that injured the actress, her Kate character was written out of the last season of the show with the story line that she had died.
Paramount Plus lists this episode as originally airing on March 23 1963 and Episode 27 of Season 8.