[Mr70]

"Also, what exactly are promos."

Promo's are fully assembled plastic promotional models that each Auto Manufacturer,Ford-Chrysler-Chevrolet-Buick-Pontiac-Oldsmobile-AMC,etc. sold to their dealerships to give away to prospective customers or future customers,like little kids.Each fragile model came in a similar sized cardbord box wrapped in tissue paper denoting name & color of vehicle on end flap.
They were usually produced by Toy store/Hobby shop model kit makers like AMT & Jo-Han to name a few,and were released in a variety of colors and bodystyles exclusive to these dealerships that Toy store/Hobby shops did not have access to.
I think they started promos as early as the 1930's and are still being released all the way up to todays current models.
All colors & styles are sought after and desireable to todays collectors.