Hi John:
It would depend on how badly the lettering is gone.
If partial lettering is removed.. ie bits of a character.... it is possible to use "Letrset" http://www.letraset.com/products/91-Lettering/ scratch off lettering to touch up the font. You may not need the exact font as you would rub off just enough to restore the letter.
Then spray the panel lightly with a photographic lacquer or some transparent clear coat. Don't over do it as it will show up heavy, shinny and ugly... just a light spray to protect the lettering.
You could rescreen the entire panel, and it is possible to do with software, and modified epson inkjet printers. which allow you to do custom screens but its an involved process.
Derek