Believe it or not, the use of the song, "Lift Every Voice and Sing," has been the "Black National Anthem" for quite some time. When I was a kid in the early to mid 70's, my mom had a friend who was the "team doctor" for a high school Football team in Newark, NJ. This team was all black. Being the team doctor's friend, I was able to be on the sidelines with the players and coaches, etc. and, to an extent, the locker rooms during half-time and at end of game (although, oddly enough, I was never allowed in the locker room of the team's home field... had to stay in the head coach's private office).
Anyway, at the end of each game, win or lose, the head coach would huddle the team together on the field and offer his general comments on that particular game. And, at the end of his comments, he'd make them sing the black national anthem, "Lift Every Voice and sing" (he'd shout out, "HIT IT!"). And the football players did so, every time, in unison.
So, it's been around for a bit.