I didn't expect it to be around that early...maybe around 1990 or so, but not around 1977. To tell you the truth, I didn't start eating the Extra Crispy variety until about 1993 or so.
Actually, Extra Crispy dates back to the early 1970s. I remember it as the commercials used a variation of the "Get a bucket of chicken, finger lickin' good" jingle that Barry Manilow wrote for them. Been looking for that commercial here on RU-vid for many years, but nobody seems to have it.
This commercial is WAY better than the one with with the yacht and music. Now I want KFC and I just watched that yacht commercial made 2018. And yes I'm comparing times of past to present.
I recall the Extra Crispy KFC from the late 60s and early 70s was a different recipe than they use now. The new Crispy recipe as well as the original is different. It's not as good as it used to be decades ago.