The 1967 seat was the last seat with no headrest...
The 1968-69 seat is similar to my 1970, the headrest is wider.
They changed it in 1970 to the narrow headrest. Note mine still has the "squared off" shoulders, reminescent of the ones with no headrest.
In 1973, they changed it to this...
Nothing at all like the old ones with no headrest. I'm pretty happy with my seat style.