Following some of the forum wisdom about using paint pens for lug lines and how to get paint in engravings, I did my first attempt as shown below. Sharpie yellow extra fine paint pen, Sherwin Williams "Gecko" green. The lug lines seem pretty durable. Up close, the lug lines are a little messy, but the original ones actually were sort of messy too, it wasn't like they were put down by some robot CAM machine.
Here is a little larger image.