Since making the initial post that you replied to I have learned a lot about the ancestry of George W. Sanders, b. 1839. Thanks to research into my DNA matches, I now have information taking his line back another four generations to his great-great-grandparents, James Sanders and Sarah Scrimshire who married in New Kent Co., VA in 1698.
I now know that George's father was Thomas Sanders who was born 1780-1784 either in Caswell NC or Sumner TN. His parents, William and Fanny Sanders moved the family to the Cumberland settlements by 1789 and were in Sumner first but by 1813 were residing in Bedford TN. Thomas married about 1805 and is found on the 1820 and 1830 census in Bedford. Don't know who his first wife was, as yet, but his second marriage was to my direct ancestor, Mary Magdalene Brown about 1831.
The 1830 census shows Thomas had four sons prior to his marriage to Mary M. Brown. Their ages range from under 5 to 20+. Only the two youngest sons are found on the 1840 census after he moved his new family to Sevier Co. AR sometime between 1831 and 1835. I think I know who the eldest of his first four sons was, Brice H. Sanders, but that is only a theory at this point. He ended up in Stewart Co. TN where he died before 1850. But I have no information about his other three sons. After Thomas died (about 1844) in Sevier, his widow Mary returned to Bedford TN with her three youngest children between 1848-50. I do not know what became of the two youngest sons from Thomas' first marriage. They did not go with her, and I do know her oldest son, Romulus, went to Texas for a brief period before returning to AR prior to 1854. Don't know who he went to Texas with, but it seems unlikely he went alone.
It is possible the answer to your mystery lies somewhere in this confusing family group, but the only way to determine that is with a proper DNA test. Would really like to see you have a DNA test. If you match my results I think we'd be able to sort out your mystery. That would be a bonus for both of us because I'd really like to find out who Thomas' other sons were.