Please let me know if you receive this very overdue reply.My sincere apologies.Yes, I agree with your theory that Lewis Wilburn m to Mary Shipp is most likely her Uncle via marriage if not related in other ways also. As you know, during this era most marriages took place between people who were related in more than merely one way.
Lewis Wilburn who witnessed the bond for Mary Shipp who m John Whitlock, is the son of Richard Wilburn who died in Goochland, Va in 1756 and Ann Whitlock Wilburn.
The Whitlock and Wilburn connections continue for many generations although I cannot determine the exact kinships.One example:Lewis Whitlock is living in the household of Burwell Wilburn in Carter Co KY in 1850.
This particular line ofWilburns and the Whitlocks (appear to go back to Middlesex Co VA during the early 1700'.
Just a tidbit here.This Shipp line is related to the Shipp line of Harry S Truman.Later on someone is named Wilburn Truman.Don't know the connection.
regarding documents that prove Lewis Wilburn is Uncle of Mary Shipp.Nope, I've never come across any solid proof.But like you, I believe it highly likely that Lewis was her Uncle.
I have some early Bowles entries in my database.Let meknow if you are interested.Again my most sincere apologies for this very long delay in responding.Somehow I just goofed up.So sorry.