The footage of the yellow Jaguar being pushed into a canyon has been used multiple times. It appeared in Murder Once Removed (1975). It appears again in The Greenhouse Jungle (1972), which also starred Bradford Dillman.
Lee Meriwether, Mariette Hartley, Teri Garr, William Sargent, and Gail Bonney are all Star Trek (1966) alumni.
Barnaby mentions his cousin "back in Tennessee" implying he may have lived there at some time. In an earlier episode he said he was from
North Carolina when someone inquired about his accent.
Of all of the Star Trek alum, only Lee Meriwether and Mariette Hartley shared any significant scenes together, at the Burbank Airport.