If you still have it, there should be a sticker on the back of the glove box & inside the lid of the PDC cover that has everything labled. If you don't have those stickers... post up maybe one of us can dig it up from one of our own.
Assuming your going to have to take the one in the jeep off/apart any how... I don't see why you couldn't cut one wire on each of the back of those LEDs, temporarily install the junk yard cluster, see if it does as you want, and maybe leave it in the jeep for as long as you can/want garaged to see if it casues any adverse affects. I'd say that would do it. OR just pull each bulb from the circut board if it will allow you to do that. But cutting one wire from each bulb should be all that you need to do.