I haven't got my trusty index to hand, but off the cuff I can say this:
Burns wrote his words [about the origin of which he left contradictory statements] to an old tune, to which Allan Ramsay had written his own words about 1720: "Old Long Syne". Then B's publisher printed it to another tune [the present one]--a habit he had; he often completely disregarded the poet's instructions, and SOMETIMES was successful. Anyway, the second tune was again old and anonymous, going to a faintly bawdy song called "I fee'd a lad at Martinmas". More later, maybe.
M