Brass U S Mail Insignia

My father found this relic hunting in the Seven Pines area of Virginia in the late 60's or early 70's. I am trying to identify what it is. It is brass and 3 ½ inches wide and 1 inch tall. I tried to do a etching since it is hard to see what is on it. One side says U S Mail the other side has an Eagle and the words NEWS 60’s or Go’s