I have found cases like this before in Oregon. What happens is you have have to live on a piece of land for a number of years before you can get a patent on it, and many people delayed things even further after that. What could have happened in your case is that the Finleys lived on the land for 30 years and then sold their rights to the claim by deed to the Ownbys.

It might be a good idea to call up a surveyor in Dallas County, and ask them if they've seen such cases before in the area.