Zimmerman in "Songs of Irish Rebellion" (1967) says: "... It seems that this ballad was circulated on broadsides before appearing in newspapers and songbooks. Eugene Davis says that Casey had for some time the idea of writing ballads to be sold at the country fairs and markets; one thousand copies of "The rising of the moon" would have circulated in Longford, Cavan and Westmeath before Casey settled in 1865."

Incidentally, Jon, the old copies all contain the verse you refer to as possibly a later addition.

Regards