67 Barracuda headlight bezel threaded studs

You might search the world over for those exact studs that the factory used. Have the custom made ?
The studs that were shown at post #2 do work if you remove the OEM welded in studs. I've rebuilt 3 sets of grilles using these 'T' bolt studs.
They are the same studs that were used at upper and lower trim on your 67 B'cuda trunk lid, Except that they are cadmium plated. Stainless or nylon nuts makes it easy to take apart again too.
While rebuilding the grilles with these studs you would realize/understand why the factory used welded in place studs here. The multiple small parts increase assembly time.