On the left, Washizaki from Riki-Oh #22, page 26, from February 1989.
On the right, M. Bison's original character portrait from 1991.
The Dictator's working name while the game was under development was even "Washizaki," in case there was any lingering doubt about his inspiration. Of course, Washizaki himself was a take on Yasunori Katō, so ripping off existing characters is apparently the theme of the day.
So they were allowed to just trace things back then?