Very nice, I wish I could do that with my PPK/S, but unfortunately its markings are all laser-etched, so there's really no depth to fill in.
My Judge already has colored markings, but for the life of me I can't tell if they're laser-etched or just factory color-filled because the markings aren't smooth, nor do they appear to be part of the metal, and in some places (namely the SN) have worn down to show that they have some depth to them.