I also owned a property from the late 1800's, but I never discovered anything exciting in it. It was just an old, unremarkable duplex. If there ever was anything interesting about it, chances are the previous owners (of which there were many) already found it before I owned it. 🙂
If you've ever been to Europe, you'll see A LOT of properties that are much, much older... centuries older than what we see in the U.S. Sometimes I wonder what discoveries are waiting to be found in those houses.