['ol Pinion head]

Pretty much spot on. Jon, I would need to go back & read my old post on this. '76 was def one year. there were some original '73 fenders that were used up on early '74 production cars, I've pulled them. In the past, I have also pulled a late '80 model or '81 model fender that only had the late style front corner spoiler mounting holes. Currently, of the T/A fenders that I have ( of which originally were made as '79 & 80 T/A fenders), they all began with both styles of stamped holes to mount either style of corner spoiler. Also up in the racking I have an NOS GM replacement fender from the late 80's, it differs in having the square hole & clip nut, vs a threaded hole for the hood hinge mtg.