I made a test panel using Rustoleum High Heat BBQ Black. It dried quickly and had a non-glare finish. It was called "BBQ Black" but it's not even close to black! It's not even close to charcoal. It was like a dark grey primer.
I'm not sure I will use it on the entire dash, because I was getting fingerprints when handling the test panel, and fingerprints are bad, especially in a car you'll be using during the hot& sweaty summer, and some bozo may even try wiping the thing with ArmorAll, thinking he's helping you get more points for a show.
If the Trim paint can hold up to fingerprints, like a vinyl paint, and some light scuffing, like from a GPS setup or a computer mount, then it'll be worth the $13 a can. Vinyl paint also do that, but you can't get it in flat black.
And it seems that every black automotive paint is made with gloss...