As Jeff alluded to, I also always thought that these "Gills" were aftermarket only. But, as Jim noted, the 1964-1/2 -1965 Body Assembly Manual does show the "Gills". They are listed as "Ornament, Headlamp Housing", (R.P.O.). The Engineering Number noted is C5ZB-13A127. The Assembly Drawing (a portion of which is attached), shows that the ornaments had studs, or pins, protruding on the backside. The attaching hardware is shown as circular, push-on spring nuts, which would indicate that the protrusions are pins.
However, all of that being said, a further look int this part reveals the following :
1) A look at the Text portions of the 1965, 66 and 67 Ford Parts and Accessories Catalogs shows no such similar Part Number.
2) A search in the same 3 Catalogs shows no such "ornament".
3) Similar results in the 1960-68 MPC.
4) No such Option is listed in any Sales Brochure that I have, nor in the list of Options in the 1965 Ford Car Facts Book, nor in the 1965 Salesman's Price Guide.
5) No similar Part Number is noted in the 1964, 65, 66, or 67 Ford OSI Books.
6) No similar Part Number is listed in the November, 1965 Ford List Price Book.
Based on the above, IMHO, I believe that Ford originally thought about including this Option, but canceled it prior to Production. Unfortunately, most times the Assembly Drawings that have been reprinted are the ones that were available in the book from which they were printed, and do not include Revisions that may have occurred before and after the dates shown on the drawings. When they do, there is usually a large stamp noting "CANCELED" on the page,
Of course, any Ford documentation which shows that these were actually available, even if for a short time, would be welcomed.
Bob