But just did a quick google out of my own curiosity... they will custom mix. Can't promise exact fidelity to the color - a lot of pigments are now obsolete in the reds due to the lead and chromates - but you might get close.

If that doesn't squeeze the juice, try Tamiya Mica Red (TS 39 IIRC) you can see the colors at tamiya.com - search the TS color chips.

Firemist had a very noticable metallic component that GM sourced exclusively innaday. I don't know if that component is being reproduced or not, but scale colors are not always 100% when applied to the model.

I bet if you shoot a few spoons and vary the primer undercoat (thinking maybe a tan or red oxide) you can get pretty close.