The C6AZ-62612A18-A, B, C, D and E Ford Headrests were an original Ford Accessory (available from the Dealers? Parts counters), and not a Factory Option. These came out, like many other Ford Accessories of that year, in very late 1966. They were not listed in the 1966 Ford Accessory Catalog, the January, 1966 Ford Parts & Accessories Book, nor in the November, 1965 Ford Price Books. It wasn?t until the August, 1966 edition of the Ford ?Parts and Service Merchandising News? (copy of appropriate pages attached), when they were shown as a ?new Ford Accessory?. They did then appear in the 1967 Ford Accessory Catalog (copy of appropriate page attached), and in the November, 1966 Ford Price Book, for $16.25 each, or $32.50 for a package of two.
Initially, the Headrests were listed as one of Ford?s ?Universal Rotunda Accessories? (copy from January 1967 Ford Parts & Accessories Book, attached), which shows the typical Rotunda ?(R-xx)? number, in this case the ?xx? being ?91?. They were packaged in a FoMoCo box, with a Rotunda label on it (pictures attached).
In late 1967, Ford was ?moving on? from its Rotunda ?Universal Accessories?, and accordingly, the Rotunda label was eliminated from the box, and the ?R-91? number was removed from the part description (copy of Headrest listing in the 1960-68 MPC attached).
This Accessory had a very limited application (1966 and 1967), since 1968 saw a change in the seats. In addition, the Optional 1968 Mustang Interior Decor Group included Headrests, although quite different than the 1966-67 Accessory Headrests. Accordingly, Ford offered a new, ?Deluxe Headrest? (copy of appropriate pages from 1968 Ford Accessory Catalog attached), now carrying as C8AZ Part Number, that more closely resembled the Factory Optional Headrests. By 1969, most, if not all, Models came ?Standard? with Headrests, and Ford no longer catalogued an Accessory Headrest.
Interestingly, the same Illustration of the Headrest that appeared in the 1960-68 MPC, also appears in the 1965-72 MPC, which was printed in 1975, well after the 1966-67 Headrest Kit was no longer available. Accordingly, there is no Text addressing the Headrest Kit in the 1965-72 MPC.
Hope this helps.
I ?rest? my case.
Bob