Wait a minute . . .
You should probably talk to the factory during the upcoming week -- they are pretty good about answering these kinds of questions. I would be concerned about letting water IN, especially if there is a layer of fiberglass insulation on top of the coroplast, just waiting to soak up the water.
In my 2012 FF, I have a layer of thick black vinyl which holds up the layer of pink fiberglass. I would not want that insulation to get wet. (And by the way, my old 2003 FF had no underbelly insulation -- just a layer of chipboard. The floor of my new FF is far warmer in cold conditions and far cooler in the heat.)