When Willie and Barney are arrested, it takes place in the redecorated office of Joe Mannix. The network may have hoped Mannix (1967) fans wouldn't notice.
At the start of the season, the profile pictures of the actors have been entirely updated, with the exception of Martin Landau. Notably, Barbara Bain's photograph now bears a closer resemblance to her character's usual appearance.
The title refers to an heir who, short of a fundamental change in the situation, cannot be displaced from inheriting.
There is no selection of agents from the IMF file in this episode.