Fender introduced the Mustang in 1964. 1965 reissues are fairly popular.
In 1968/9 They introduced the 'Competition' Mustang, as well as a regular Mustang, both of which could feature a painted headstock.
Is yours a 1969 reissue, or a Competition reissue?
Fender Japan also makes Mustangs in finishes and headstocks that weren't originally available in the Vintage Fender era.
I think the headstocks are better painted on stangs.
ps. post pics.