So I almost made a deal on a double wide display case and at the lat second, seller tells me he is missing a full self. What kind of negotiating leverage should I have on this? I originally was under the assumption there wasn't anything missing, but I am going to need a barrel lock and also a full width shelf. What do these pieces cost to replace and is it polycarbonate or acrylic? Anyone have a full lay out of actual size for a direct replacement? Thanks guys! I am most have a double wide!