I'm not versed enough in mold making to tell you how you could use that cowl to make a mold. What I do for one-off parts is get some green florist's foam, glue the blocks together until they're big enough, draw my front, back and side views and have at it with a carving knife and sanding blocks.

First layer is light cloth to make the inside smooth. Then a couple layers of heavy cloth diagonally opposed, followed by a layer of light cloth. How many heavy layers you use depends on how big the cowl is and how stiff you make it.

You can get florist's foam at craft shops (Ben Franklin, Michael's, etc).