The intermix of my numismatic and philately  hobbies identified this medal. Also, I’ve  seen an image of an  un-cannibalized specimen in its original intact Medalist First Day Cover (FDC). High probability this specimen was cannibalized for its silver content.

You will see the exact reverse on a medal I identified in a previous blog.

https://thehawaiiananumismatist.com/2013/03/23/new-find-captain-james-cook/