I think you could make this work (and this is me TOL, I haven't done this) if you removed the faceplate, scanned it in, double check dimensions so your scanned image is exact. Then use a program like indesign or even photoshop to redo lettering on a layer above the scanned in layer. Use these programs (or anything similar if it works for you) to make a template too of the size of the faceplate, where the cutouts are for the Pots and switches etc. So what you would end up having is all the text along with a thin line to designate what needs to be removed, save this as a psd or a png (you want only the text and lines to print out so the background needs to be transparent)
Now all you need to do is have this printed on thin clear plastic, trim out where the pots and switches are with an exacto and adhere it to the original faceplate (once you've removed what's left of the old lettering) You'd have to look into what plastics you can print to and what kind of glue will dry absolutely transparent