It depends! They come in different variants, and the media has been really good at melding together the 'hillbilly' and the 'redneck' stereotypes, among others, for one reason or another over the course of the last century or so.
The trope seems to have strong Scottish origins, transplanted to Appalachia with immigration, and you can track the typical 'naive travellers threatened by hillbilly' story to the old scottish Sawney Bean story as presented in the Newgate Calendar, which may as well have had ulterior motives too.
For certain is the march of the "Red Neck Army" coal miners in 1921, so 'redneck' has certainly been established as a popular concept at this time. more