RacerVW did swap an A3 with an A4 faceplate in the very early days and reported on the Yahoo forum that it worked. He mentioned that the faceplate, display and a couple more components are one unit which get replaced together. Other than that I have not seen any other reference to changing faceplates.
Craig, I'm afraid you have to remove the 3 screws under the display. The procedure for removing the face plate is the following (in order):
1. turn the unit on, and place the screen in the 'open' position (screen flat). Keep it this way (so don't let it close it, turn the power off with screen flat)
2. remove the 3 black screws under the display. Yes, they are damn tight...Use a good screwdriver with the right fit. Don't use the small watchmaker screwdrivers. You can't get enough grip with these ones. Hold the screen when you remove the last screw
3. Take the screen carefully out of the rails. Release the flatcable connecter from your screen to the RNS-E. The screen is loose now.
4. remove the screws on the left and right side of the RNS-E (4 big screws on each side). Also remove the 2 smaller screws of the faceplate on the underside of the RNS-E
5. remove the plate on top of the RNS-E (the one with the RNS-E type# on it)
6. disconnect the flat cable (the one from the faceplate to the RNS-E) carefully
7. release/fold out the 2 clamps on the left and right side of the RNS-E
8. Take the faceplate off
To fix the plate: follow the procedure in reverse order.