I have an 8 oz rattle can of Dupli-Color Perfect Match "Duplicate's Original Honda Colors." BHA 0905 Avignon Blue Metallic (B26M) I'm a huge, longtime Pontiac fan. It does a good job of representing a 1966 and up Pontiac engine factory color. Since it's automotive, I would use a good primer and do the spoon test.
I also have a 1/2 oz of Model Master Enamel bottle labeled as "Pontiac Engine Blue Metallic. The number on the label is 2728. It's a perfect match. Hope this helps you in your search
Good luck!