Definitive answer. During the period the various distributors were independently owned. I worked at the port of entry for Continental Cars, the distributor that covered most of the central US.
Each distributor designed and purchased its own accessories, and that includes both a/c and radio. There were some common items, such as luggage rack and stripe kits when there was a major sales campaign going around. For example, the TR7 was not moving, so BL (USA) arranged for a kit that included luggage rack, white spoke wheels (they were confused with Jeeps I suppose), stripe kit and vinyl roof.
As to the a/c question in particular, it simply depends on the section of the country the car came from. We did not allow the dealers to install any accessories, doing them instead at the port facility in the hopes of better quality control.
Any car that was sold from Continental's dealers was fitted with an ARA air conditioner (best I remember, that was the brand), and Panasonic radio. The radio mounting kit was designed by myself and purchased from a company in New York city. Every car was given an undercoating treatment before being shipped.
So the answer really is, then, whatever you have might or might not have been in the car at the time of retail delivery. It might have been installed at a dealer, at the distributor level, or at some local shop down the road from the dealer.
What I can tell you for certain is that there were no a/c units installed in England, or Belgium (where the cars were loaded and shipped to the U.S.)
All TR6s in the U.S. came with wood dash. Hope that helps a bit.