I know Chevrolet was a sponsor for "Bewitched" and often would place interesting current cars in the show. '70 Impala convertible with Light Monitoring, '69 Camaro RS etc. I think the show ran 1965-70.

"I Dream Of Jeanie" often had Pontiacs; I remember a '65 GTO convertible on one episode.

"The Brady Bunch" usually ran Plymouths through 1968-73, including a '71 Barracuda convertible that was turned into a '72(!) on one episode. In 1974 they switched to Chevrolet, and Mike Brady ran a '74 Caprice convertible. I used to have a bunch of pictures from an online ad for a '71 Dodge Challenger convertible that was used on "The Mod Squad". 340, column-shifted Torqueflight, A/C, wire wheel covers, luggage rack on the trunk...