Sealing the trunk/inner fender area

[aex125]

Does anyone know how the factory sealed the trunk area where the triangles meet just inboard of the rear wheels as I am trying to ensure no water or dust enters the trunk? The area I'm talking about is where the upper trunk shelf meets the body/inner fender area, where 3 frame triangles meet up. It doesn't look like the shelf could be made to fill it in, so I was wondering if a rubber flap was used or if there is a piece that covers from the bottom side. I am working on pieces that seal by wrapping around the top side of the triangles, but from the pictures I have seen, it doesn't look like that is how the factory did it.
   Thanks,
   Jay