Rich R: According to ³Folksingers and Folksongs in America² by Ray Lawless (Second Ed., 1965), the Gateway Singers¹ LP ³At the Hungry I² was released in 1958.
The other Gateway Singers album you mention, 1959¹s ³On the Lot,² is news to me and is very interesting because it contains TWO songs closely associated with the Kingston Trio-- ³The MTA² and ³I Won¹t Be Worried Long² (which I assume is the same song as the Kingston Trio¹s ³Worried Man²).
The Kingston Trio¹s recording of ³MTA² was released as a single on June 18, 1959. (It was taken from their album ³At Large² which was released the same month). According to the book ³The Kingston Trio On Record² (Kingston Korner, Inc., 1986), ³the group first heard the song from Will Holt.² Holt included ³MTA² on his 1957 Coral LP ³World of Will Holt.² (That album also featured the original recording of ³Raspberries, Strawberries,² which the KT also recorded.) But clearly, depending on when in 1959 the Gateway Singers recorded and released ³On The Lot,² their version of ³MTA² could also have been a source for the KT.
Parenthetically, we know that the KT covered many songs previously recorded by the Gateway Singers such as ³Reuben James,² ³Oleanna,² ³This Little Light of Mine² and ³Saro Jane.² And it has been reported that Dave Guard modeled his between-song patter after Lou Gottlieb who was with the Gateways until after they recorded ³At the Hungry I² in 1958. Then, according to the liner notes on that album, he left to complete his PhD dissertation and was replaced by Ernie Sheldon.