Anyone know where I can get the interior color code (not the trim tag code) for my '82 Pace Car?

I need to get paint mixed to refinish/repaint the dark blue interior plastic panels, but the 26G trim tag code isn't the actual color code. Even "26", according to my paint shop, shows a bunch of different colors.

I can send them a sample to match from one of my old panels, but they could mix & ship quicker if I can give them the exact code.

Any insights are appreciated.