There are mistakes in Flanders esp in the bio section where the collectors got confused about the names of relatives. So in this case--Rebecca Hoyt and Rebecca Greenough are the same person because she was adopted- Rebeccas Hoyt is not Rebecca Greenough's grandmother as Flanders says. Nor is there a Rebecca Hoyt that is her grandmother as far as I could tell by checking briefly the genealogy. Therefore who knows if the assertion is correct. If it is- this dates back to the 1700s.
Flanders G can be traced back before the Revolutionary War (1776) by tracing the ballad through family lineage. Even in this version there is a confusing statement at the end.
I can take a peak at the Roud index and email you some changes,