You may be onto something. I couldn't find that panel in FAST but I found some sort of speaker setup in that area...
Bottom right corner, inside the enclosed box.
edit:
If that panel were to exist it would be in this diagram, but it is not. Perhaps it has something to do with Diamond Selection or maybe Autech made? If not, than its just custom made with a Nissan sticker up top. I mean, it is a black interior piece in an otherwise brown interior vehicle.