Yeah...the "jackpot reserve chamber" seems to be "for show" on the Ginza models. This seems to be a "grey" area...as it seems so clear as to why it was used, but when displayed...not always used.
As far as your machine is concerned, it has so many little details that make it stand out! As mentioned earlier, the signature ball tray, the ball plate where balls are inserted has nice engraving, even the "Ginza Co LTD" sticker is COOL! More pics of the back would be AWESOME!