Big Mick,
Pete Seeger once mentioned to me that he met both Fred Hellerman and Ronnie Gilbert just after WWII when they became part of the folk revival scene. Pete also mentioned that Fred was eight years younger than he was. Since Pete was born in 1919, I took it that Fred must have been born around 1927 which would have made him about 14 when Woody, Pete and the Almanac Singers started singing "Reuben James."