Here is a photo of the Ad for Oliver's plow Hitch-Up
Sales Promotion. This two page Ad appeared in Sucessful Farming Magazine's July 1966 issue.
I was working in the Omaha Branch at the time. To my knowledge the Charles City Plant only painted one 1850 purple. It was used in the country wide GROWING "O" show at Iowa's Floyd County Fair grounds. It probably went on to one of the Branches for their use. The paint mix was provided to all Branches. The Omaha Branch had Clyde's Body Shop in Millard, NE paint two for use in Domonstrations and Fairs. Those tractors were stripped of the purple paint and repainted before being sold. The color mix was a color available on the years Continential cars.
I don't think there is any way or anyone that knows how many or what models were painted purple in the day. I know of two that have been painted purple recently, one of tractors is in the current Classic Tractor Calendar.
By the way the promotion was very successful.