Most of the cars have nothing there,possibly some type of foam or caulk to seal the hole.Have you tried bolting it on?I thinlk the front flange of the hood is not a single thickness so the nuts will not screw down all the way.
Is the piece you're talking about the front edge Diecast? ...or the hood bar down the middle? If it is the hood bar, then it just uses speed nuts. If it's the Diecast (which I think is what you're talking about), it uses speed nuts and a bent sheet metal spacer. I don't have any off the car but if you give me a day or two, I can remove one and get a pic for ya.