Actually, the Weavers recorded it before the Kingston Trio - who learned it either from the Sandburg collection that was published in 1927 or perhaps from one of the many field recordings that were later made - including Alan Lomax.

The point is, the song was a regional song that became "popular" to a wider audience due to the work of the collectors. Because the song became so widely known, does it cease to be a "folk song"? Is the Beach Boys version not a folk song because they use electric instruments?

It is gray areas like this that get us into such discussions which are really a turn off to audiences who do not share the same passions. I find it fascinating.