This was posted on the Bumpside forum. 1967 Assembly Plant Paint Booth Gallery - FORDification.com
The article is about 1967 but there is also some 1966 photos at the bottom including this one that shows an F100 with mirrors on. Interesting reading.

[img]blob:https://www.ford-trucks.com/31cdf940-2947-435a-a98b-1521585103af[/img]

 

Love it when there is no filter from the old timer and they give true insights.