The letters on the keyboard were covered with some "stuff" from the factory to prevent them from rubbing off, I imagine. The dye didn't seem to bond with this stuff, and so it was removable just by pulling on it with tape. The removal of the dye exposed some of the original color of the keyboard as well as the original letters, so like I said, not perfect, but usable. You're actually seeing the original letters with an aura of beige.
As for printing on the fronts of the keys, that text is lost.
This method is definitely no replacement for using CDTV keys if you want a pretty keyboard, but I'd already used a set of those on my 1200 and figured I'd try something else.
There was plenty of vinyl dye on eBay available last time I checked, the kind I used came in a spray can.
