I think that there was a better technique to do it. Depending on shape and configuration of surface with printed markings, I think that the best way is to scan them - put the surface where the markings are the boombox on top of scanner, and scan them. Your black markings are symmetrical to red ones, so all it would take would have been horizontal flipping, selecting red color and adding numbers below.
Than you should check with local print shop, what kind of printing they do. I think that it is the only proper way to replace all worn out markings, especially after full paint-job of whole boombox. I think that even in factories they've used screen printing, and that is something every decent print store can to.
I stand to be corrected, and would like to hear if someone else has info about such markings are done in factories. There must be someone here on forum working in some company that marks their products in same way, or someone who knows somebody.
Found this for example
http://www.uniquepadprinting.com/capabilities/surface/painted-coated
http://www.uniquepadprinting.com/gallery/electrical
