Threaded anchor that slides into the trunk hinge on each side. Sold individually, two needed per car. These are for Cougar and Mustang built before approximately 3/31/1971. Look for bolt spacing of 3 inches on those trunk lids.
Ford number 6242752.
*Note - Trunks after March 31, 1971, used a different anchor plate. Bolt spacing of about 3 inches.