Or, you can just try to match actual prototype paint chips.
https://www.flickr.com/photos/timboconnor/17098035956/

Putting a label on a bottle does not make it accurate. Tru-Color
is known to sell the same color with more than one label.

Tim O'Connor


 >> Tru-color makes two versions... one for pre-1945 cars and one for post-1945.