There's an eraser on the marker. I think Bob is right -- that whatever the buzzer is supposed to be or do, that rectangular thing with the logo is it.
-Jason
I must confess, I also originally thought the "prop," was an eraser. I doubted it when I saw both the eraser on the marker itself, as well as the "buzzer," notation on display. That's why I'm led to believe the "prop," is the buzzer! Assuming that the prop has "Jeopardy!" embossed on it, maybe there are also plans for regular J! games later. A press release mentioned new "Card" games are planned, both of this and WOF, but no such products were shown at the Toy Fair.
Although everything on my part is an assumption, I think the board may have grid layouts on both sides, complete with similar, permanent monetary covers. I just hope that (if my hunch is right), the "Double Pop Culture Jeopardy!," topper is misplaced because $200-$1000 values are currently Round 1 figures, not DJ!
Also, the notation about 1,260 clues leads me to think, not including FJ! clues, there would be enough material for twenty-one complete games. I wonder how much it would be whenever it becomes available.