I can't speak for the '66 but it was standard on the '67 GS400 and GS California. Here is the page from the '67 assembly manual showing the stripes and they just modified the sheet from the '66.
I have some factory lit here which states 'Dual Paint Stripes' were standard on 66 GS. I'd have to dig to see if it was standard on plain Skylarks.
I'm pretty sure all '66 GS's came with stripes. I used to have the '66 chart on my old computer that crashed and now I can't find it anywhere on the WWW.
Although this isn't a Buick I've always appreciated this PIC. Could it be that I spent 37years working at General Motors as a Manufacturing Engineer, supporting the Trim and Chassis departments with assembly tooling such as this pinstriping fixture attached to the side of this GTO that piques my interest? Thanks,
Thanks for the info, kinda what I though, cool picture. What is the best way to apply the pin stripes to make them look original?
This tool is similar to what was used to apply the stripes at the factory. We have one and have used it on a few cars. It’s not as easy as it looks. If you have someone in your area that is an old-school pinstriper they could knock it out by hand and probably look better than the roller tool. https://www.eastwood.com/beugler-pro-pinstriping-kit.html