I just went to a hardware store and bought a spray can of semi-gloss black. Tried it on a junk piece, and it matched right up. Years later, it still looks great. The lesson is that there should be a variety of matching paint products.
Buick originally used acrylic lacquer. It wasn't buffed out, so it's not a 'full' gloss. I used gloss black 'classic lacquer' from Plasticoat. The black on the chromed dash is a semi-gloss. I used a urethane paint with a bit of flattener to match it.
