That I tend to doubt.
The vote on the flag was 65%/35% and the ethnic breakdown of Mississippi is 62% white/37% black.
I'm going to guess that the vote on the flag split pretty evenly down racial lines.
The most pro-old flag county was Tishomingo which voted 91% to keep it. Tishomingo is 95% white and 3% black.
The most anti-old flag county was Jefferson which voted 83% to get rid of it. Jefferson is 87% black, 13% white.
The most evenly balanced county was Yazoo which was split exactly down the middle: 4370 votes vs. 4370 votes - 50% for, 50% against. Yazoo is 54% white and 45% black.
This would indicate that very few blacks voted for the old flag, and that very few whites voted against.
So much for freedom of expression. The descent into liberal totalitarianism continues.