Having been away for sevaral days I missed taking part in the discussions regarding the Kingston Trio and the Gateway Singers.
With respect to the chronology of the Gateways, it is the fault of the record companies that makes dating difficult. Many, (Elektra, Capitol, Decca come to mind) did not date the recordings on the jacket or the disc (except perhaps in a code), thus we must rely on our memories, or some clue in the liner notes, or in the patter of the recording (i.e. reference to an event) to narrow the chronolgy. Think of it as discography archaeolgy.
Thankfully, in the CD re-releases, the packager has access to original production and release information, and often includes it...but I'm not aware of Gateway CDs.
As to the Kingstons, they deserve a place in the pantheon, if only because so many of us developed our awareness of folk music from their work.---John