There are plenty of clues if you actually study the material, who wrote them, stylistic clues, as well as the many that are based on historical events.

****Elsewhere you said they were too busy earning a living to make folk songs****Not quite what I said, but fairly close. The vast majority of the rural population in the early 19th century lived in abject conditions one step above slavery and there are multiple reasons why they would not have had the inclination to make their own songs, particularly protest songs. Those that did have the creative urge and there were probably enough very rarely came into contact with a printer, and that is obviously how the majority of the national corpus songs were spread around the country, whilst also allowing for migratory workers.

****The corpus you are talking about were covered time when the tradition was dying**** And this is relevant because? I don't remember anyone stating otherwise.