I went down and checked my stash, all the "star" plug boxes (box of 10) don't have any date and have the big star on the box. The later 68-72 Autolite Ford plug boxes have the "ghost" GT40 on the box and the 1966 copyright. I even checked one of those round Autolite tune up kits from 1971 (had a promo offer inside that expired in 72) and they had the 1966 copyright on them. My camera battery charger took a shit so I couldn't take some pic's but I found 2 pic's on Ebay that show the early and late boxes... Just curious, does your Cougar take BF32's or BF42's ? I know 428's pretty well, but 390's, not so much....
The 1st pic is the "star" plug box, The second pic is the later Autolite plugs..
Hope this helps, John