"....Or even pre-1960?"
Mike Waterson almost certainly learned from the BBC recording of Paddy McCluskey made in Antrim in 1953 (collector's note below) - McCluskey was also credited with giving the song to Sam Henry.
Jim Carroll

LAKES OF PONCETRIN, The        
Singer: Paddy McCluskey                                 2.45    20031
Clough Mills,
Co. Antrim.
5.8.53 (P.K - S.O'B)
'Through swamps and alligators ....'   
(10 verses)
Song describes how amid the dangers of the alligators a handsome Creole girl offers accommodation and faithfully refuses an offer of marriage. The man leaves, saying he will remember her kindness and drink a toast to her on every social occasion.
See Sam Henry Collection, 619 for this version noted from the same singer, where the title is given as 'The Lakes of Ponchartrain' (probably more correct), with a note that these lakes are five miles north of New Orleans.