To read the original thread and discussion on this topic go here- LINK
once you find the code, here's the key:
Also note that you'll only have one number on the trim tag. For instance solid light blue is 507. I believe that a white top/insert (if you had the side trim) would be a 537 (shown on the second pic only - a 1966 chip, but same logic applied).
Attachment 874252