Through some keen detective work I have always believed that the dark blue metallic flake gelcoat that was used on the 1966 Batboats I and II was the same used on other 1960s Glastron boats such as the Jetflites and other models.
There is a 'Metallic Blue' Jetflite on eBay right now.
If one wanted to Pantone color match the blue and measure the size of the metal flakes for a Batboat project, this is probably one of the boats to do it with, IMHO.
Coincidentally, this comes with the same motor mine came with. '58 Evanrude 35 hp.