It's Ford p/n 380264-S2, and is called a "Spring Nut". The originals were made by Pal-Nut, now Tinnerman. They do not have an "exact" replacement. Their current catalog has the part in form factor, eg - the right look, but not the correct size. There is a "spring nut" of the correct size, 3/4 inch OD, 1/4 inch ID, 0.025in thk, in the Tinerman Catalog, but does not use the eight prong retaining mechanism. Ref p/n 138870 (T99220-171). I've "scored" surface with a Dremel tool diamond saw blade to "replicate" the eight prongs. The final product is painted so detection is difficult.
This is also used on 67 Fastback lids thru at least May of 67, Shelby included.
Some "pressure" on Brant or Scott may be needed to get some made.
Jim
