1965 Martha Washington "Half Dollar"

Saw an elderly distant relative at the post office. He beckoned me over to his car and showed me a Martha Washington "half dollar," as described here: https://www.coinworld.com/voices/wh..._dollar.html We were both stumped by the lack of denomination. I suggested it may have been a Mt. Vernon souvenir.

He was not sure where he had acquired it; but he served for decades as a rural postmaster, and may have taken it as a half dollar, and put 50 cents in the till to keep the coin. It appeared to have significant wear on the sides, although that may have been a feature of the pattern. It did not appear to be one of the 2019 restrikes. It was not evidently copper nickel as described here. https://en.numista.com/catalogue/pieces356278.html There was no copper visible at the sides.