Hello helpful friends!

I am now in the midst of my 2nd restore/cleaning/rebuild and I've got a weird thing. The upper base has a huge hole in the middle of it.

When I was taking it apart, the jackpot back was covered with masking tape. Do I need to do the same thing when I put it back together? Won't the masking tape block the light coming from the little bulb when a jackpot hits? Ooh, also, why was there an extra lightbulb rattling around inside of that same area? Should I use clear tape? It's a Nishijin B, I think. Here's a photo of the big hole.

Thanks so much for any advice!

aj3y499.jpg