I address that topic and provide a couple links to discussions on that in my "Kiss Yer Cousin" Rye Kentucky Common Ale
thread Evidently two different listings of the beer, in two different "handy" books don't agree. One says sour and one doesn't address it. Based on my readings I believe they weren't intentionally sour, as a style, though some may have been sour simply from poor brewing practices, while others may have been brewed by moonshiners who obviously brewed sour mash.
I look at them as a particular regional syle, that had variations from brewer to brewer.