The Frats (above) didn't form up until 1951. I don't think they recorded Day-O until the late 1950s after all the Belafonte fuss had died down a bit.

Small world tho. Manuel W. “Manny” Warner, the man behind the Frats Quintet U.S. record label (Ritmo,) was also one of the fellows behind Irving Burgie's first live venue (The Blue Angel, Chicago, with baritone Jean Fardulli.)

Still, as mentioned elsewhere, the basic theme of the Jamaican banana boat loader's song goes back a long-long way.