All I can tell you is that the round images (painted on the surface or decals or whatever) are traditional Pennsylvania Dutch so-called "hex signs." The one in the fourth photo says "Wilkum," which is "Welcome."
In case you're not familiar with these, you can read about them here:
https://en.wikipedia.org/wiki/Hex_sign
And see many more examples here:
https://www.google.com/search?q=pennsylvania+dutch+hex+signs&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjr...
Whether they are original to your piece or added later, I cannot say. And whatever it may be, I'm reasonably sure it is not a bucklet for drawing water from a well.
Sorry I can't be of more help.
