It looks the right size for a buggy tongue tip, rather than the thimble in a pic I just took:
Buggy tips can vary in size, and larger ones on wagons. But they should be brass which wears better. All the tips I find have a spot worn through from the tongue dragging on the dirt when they push the buggy away from the horse. into the barn/ They also should have one small hole drilled on the side, for a screw to hold it to the wooden rail (this pic shows the worn spot, and some roots growing out of the screw hole)
run a file on it to see if copper color or a yellow-er color like brass