So the numbering and hash marks are modeled into the part, and a layer of paint blotted in, and allowed to dry… then sand.
This was a test on a bad part, that was already sanded once (thus the partial fill here and there). This was done very hastily just as a proof of concept. I’m certain you could make it perfect, with a little care.
But a quick and easy way to get it done!
Line width and depth of cut are both 0.017" in this case… the characters are 0.105" tall (for reference/scale)