New OBW LL Bean - fiberlass or aluminum?

Just got a new OBW, LL Bean model and when I moved the magnetic ribbon from my old car to the rear hatch door of the OBW, much to my surprise it would not stick, no matter where I put it on the hatch. Had to slap it on the side, next to the gas tank filler door instead.

So what's the hatch made of: aluminum or fiberglass???

Thanks, Gunni