I did it with Guile one fateful Dec. 23 afternoon in my mid-teens, before a time anyone was graced by Mario 64.
I later learned that day, Dec. 23 is Guile's fictional birth date.
When you rack up all the rounds perfectly, you can finish the game in excess of 1 million points. Beating M. Bison perfectly gets you an 80,000pt bonus. My final score was 1,001,000 pts. The other sweet part of the ordeal is getting to see those credits roll, which are one of my all time fav staff rolls.
But my memory may be fuzzy. I remember blocking special moves incurs damage, while blocking regular attacks does not. I never got hit by a standard attack, and I don't recall making contact with any special attacks. If I took any damage, I wouldn't have gotten enough "perfects" to build my score so high, with such a clean number.
So yeah, I did do it. And I've been a worse fighting game player ever since. Until SSBM came along.