From a Chevrolet Accessory Sale Brochure
The demand for in-dash factory air conditioning or GM trucks greatly increased during the 1960's. (Automobiles had this feature available since the mid 1950's.) An under dash 'box' (Cool-Pack) was available on trucks since 1958, however, this unit was dealer installed and took up much cab room especially for a third passenger.
In 1965, Chevrolet (not GMC) offered the first factory in-dash system. As it was introduced in a pre-existing cab, a custom non-metal panel was designed to fit over a new stamped larger dash opening. Its three movable vents could blow cool air on all passengers!
This new air conditioning panel covered the portion of the stock dash that held the ash tray. Therefore, engineers created a small under-dash slide in ash tray just for factory air Chevrolet trucks in 1965-1966. Unfortunately, few people recognize this small ash tray once it becomes separated from the truck in a salvage yard. This will be an almost unobtainable item if you don't have it on your truck!
