Threaded anchor that slides into the trunk hinge on each side. Sold individually, two needed per car. These are for Cougar and Mustang built after approximately 3/31/1971. Look for bolt spacing of 4-1/4 inches on those trunk lids.
Ford number C9AZ-6242752-A.
*Note - Trunks prior to March 31, 1971, did not use this anchor plate. I think that they had a bolt spacing of 4-1/2 inches.