Ford used a paint very similar to GMH paint, Steve, so you're near right on, but these days, most like to use clear over base and use a matting agent in the clear to bring the sheen to acceptable levels for concours. We've also used, on more 'correct' concours cars, hardened basecoat, as it resembles the very thin film thickness that Ford used and has better durability than Ford's paint. With the correct amount of hardener in basecoat, it has the perfect sheen, too. You'd have to check paint brands, as not all paint brands allow hardening of their basecoats.