I'm not sure EXACTLY what you want. If its the white lettering for the guages that says oil press, or amps, oil ect then Czechman has some that are made to place on the metal piece and rub the letters off on it. I have set and they will work nice. I believe theyre about 8 bucks for a set.....if this is what your talking about.
http://www.pbase.com/czechman/instrumentsIf your looking for letters to go in the letters of C H E V R O L E T on the piece over the radio grille most vendors have vinyl letters fairly cheap. I ordered my white vinyl "block style" letters from Carter or maybe it was Classic Parts and put them in place. I think they also had black letters.
Hope I'm on the right track and this helps.