Interesting. OK, so it sounds like they used the panels to "box" the area to make it look better, rather than follow the contours of the glass?
OK, so I'm not there looking at your boat, but I work on a lot of them. With what you are saying...
-- First, if the panel is thick enough, even with the gap, it will still provide more than enough structural strength for a table. Add another backer plate if you want - like a 8" square piece of plywood or HDPE as an example (or larger if you want). If you want to get fancy, go ahead and wrap/staple it with carpet.
-- Second... it "sounds" like the panel is screwed to chocks that are likely glued to the glass to provide "nailers" for the panels. In this case, the panel is likely screwed to the chocks. Use your fingers and feel along the edges of the panel (especially the corners" and you would feel the heads of the screws that are hidden/buried in the carpet.