The screws for headlight bezels that attach directly to the fender use a clip nut and sheet metal screw. The ends of the grille that attach directly to the fender use clip nuts also. The top of the grill to steel grille header uses a large head plastic push pin. there are angle brackets that attaché the backside of grille and uses hex head bolts. As a very last resort, I can take some of my fasteners out of my car to see the size. Usually the hex held bolts are 1/4" -20bolts. I can remove some of the screws if no one else has the information handy. Just a pain to remove parts. Someone over at the ebodies.org website may have the info handy.
Terry