Posting this for a friend. He found this button at a homestead that probably dates to the mid 1800s. It says Union Made at the bottom of the horseshoe. I've only been able to find that there was a clothing brand called union made, but haven't found any other buttons similar to this. The back is still pretty cruddy, so I can't really see how it's made. These were the pics he provided. Any info would be appreciated. Thanks.