For now this is only a speculative theory, nothing more than that.
The New England Examiner tell us that Dutch and Hosea escaped from a jail at Kettering, Ohio on March 8th, 1877. It also mentions that the citizens of Kettering don't know how it happened, only Sheriff Carmichael knows but he was too embarrassed to even give important details.
My theory suggests that maybe Uncle was involved in the ambiguous escape.
Why I think that:
1. Uncle lived in Ohio until he met Dutch (1849-????).
2. Uncle claims that he and Dutch go way back (Chapter 6).
3. John Marston will comment that when he was kid, Uncle was already old, this might not be just a joke since Uncle at that time would've Arthur's age or a bit more, depending whether or not he remembers Uncle being around exactly in 1885.
4. It's not a coincidence that this important event occurred in "Kettering", Ohio. I'm aware that the trivia section states that Kettering technically didn't existed back then (check the page) but I don't think that it was a mistake, because some things are different in the world of Red Dead Redemption even tho it is an historical saga. Plus, Uncle mentioned that he arrived in a new city after losing both of his parents at the age of 9 (1858), that could fit perfectly with the number of people living there at that time.
I know that my theory has holes and leaves a lot of questions but it popped in my head when I was thinking about different arguments against "Uncle Is Red Harlow" for a video.
What you guys think of this?