I found this button at a pre civil war house. In the city of St.Charles Missouri
is this a Missouri 5th infantry Regiment button? If so is it rare? Thank you for your time.
Catfishjim
Pretty sure that is a collar disk. I can't tell from your picture if it has a plain or stippled background. It would probably date from about 1924 -1937. Let's see a picture of the backside, please. The attachment type will also help date it.