I currently have my chrome side moldings off ATM, as I'm trying to achieve a de-chromed look.
Whilst they are off I decided to do a little experiment with them and painted them body coloured and coloured the lettering in before clear coating them.
Still unsure if I want to refit them of not, so they're just sitting on a shelf in the garage.
If you were wanting to just paint the lettering then I would suggest a good clean with a wax and grease remover inside the letters and some gloss black automotive paint with a fine artist brush and a steady hand!!!
As it is slightly textured in there the paint should stick quite well.
It took me approx. 3/4 of an hour to hand paint each side with them on a bench and being able to move them around to make sure I got it all without making any mistakes..............have patience.