I matched the color/gloss from an NOS cowl cleaner that I own when doing an L48 auto (ThermAC) cowl cleaner a few months ago - the best match I found was Dupli-Color acrylic enamel DA1603 semi-gloss black - to me, a dead-on match when it dried (very glossy when wet). I compared the 2 side by side, and could not see a difference in gloss or texture. Watch the temperature when you spray, too cold and you'll orange peel a little (but then again, factory paint was light years from perfect !).
Jerry has good suggestions in the '69 Definitive book's part finish section if you want a better guide. If you don't like spray bombing parts, a good auto paint mixer can get you there from Jerry's gloss percentages/recommendations. Just my opinions -