Full circle
We do, actually!. Recent research proved there are melanosomes in some fossils/imprints, which were previously thought to be bacteria. This gives us a fairly good idea of the colouring of certain species. Check out this sinosauropteryx:
I highly recommend reading the book Dinosaurs: New Visions of a Lost World. It’s fun to read, has amazing illustrations and was written by one of the people who discovered this.