Let me add some others to the mix:
Picture 1 - Two long bracket types before I cleaned them up. Straight hook end pair came off my Oct 65 San Jose "K" car, the bent hook end were "payment" for bead blasting and painting another pair. I think the bent hook end is used in later years. They were "very difficult" to remove with the dual exhaust system in place, which is another reason I assume that many were left on the cars.
Picture 2 - A close up of the nuts used on 64-67 San Jose brackets. These are the same nuts used on 64-65 front bumpers and 64-66 rear bumpers for the bumper to bracket bolts, 374358-S8.
Picture 3 - I took these off a couple of San Jose 67 Mustangs but all I can remember is they were not dual exhaust cars. A third set went on a May 67 San Jose "A" code single exhaust as a replacement. Note the lack of a "keying" bump on the upper mounting surface.
Picture 4 - This pair came from a single exhaust 69 Mustang including the hardware shown, plant unknown. Note the locking pin on the hex nut's surface.
Marcus, if you want to use these, OK. If you want the raw photos, send me a PM.
Jim