We handle the DupliColor brand of spray paint in these cans. I gathered up quite a few original valve covers and air cleaners in order to choose the closest matching color. First, I will say that the colors slightly varied over production times.
Second, and most importantly, those caps on the cans are not an exact match to what is inside.
Anyway, in my opinion, the DE1606 is the closest to what starting being used in 1966.