Just to amplify on the observations above by Steve Parkes, Sara Grey's version of this ballad, with the "special" (pistol), and "little Robert Ford" as the footpage places it as likely a Madison County, North Carolina version. Cas Wallin sang it that way, as did his relative Dillard Chandler. Both have versions available on CDs, Cas's on one of Mike Yates's releases though Musical Traditions, and Chandler's on the Folkways album "Old Love Songs and Ballads," recently reissued as "Dark Holler: Old Love Songs and Ballads."

The joke, of course, is that "Little Robert Ford" is also the betrayer of Jesse James. When Wallin sang the song, he paused after the verse mentioning Ford, chuckled, and said, "he busied hisself, didn't he?" This showed, I think, that he was in on the joke!

In general, it's well and good to speculate, but unless an earlier version turns up in some manuscript (which does sometimes happen), it isn't likely that any version will push the date back to before 1611. It's always more likely that the details which pin it to an earlier date were added in modern times than that they survived in oral tradition undetected until today.