The silver ring is a great find too. It is a "Son In Service" blue star ring that a mother would wear to signify that she had a son serving in the war. Yours might be from WWI. What a great piece of history.
Yes, on horseback. The postal rider on horse was actually the official emblem of the Post Office Dept from the latter 1800's until the Postal Reorganization Act of 1970. I'm guessing the button I found is from the teens or 1920's.Is that postal worker on horseback? If so that’s an early one congrats!