Good find. A guy in Wisconsin(?) reproduced those about a decade ago in really nice quality, and sold them periodically on eBay and probably elsewhere for surprisingly reasonable money. Think he's out of them now, and it didn't do me any good anyhow, since mine's a 770 and not a GT. If I found a piece like this what you found, I'd immediately send it down to my rockstar plastic-repro guy in Australia.
It is rare and in super good shape. I have one for my Lancer but I am having trouble with it falling out. There is not much holding it in to the chrome bezel.