1928 United States Assay Commission Medal. By John R. Sinnock and Adam Pietz. JK AC-72. Rarity-4. Bronze. MS-63 (NGC).51 mm. Gorgeous deep golden-brown surfaces are boldly defined overall. There is slight variation to the color on the reverse that seems to be the only impediment to an even higher grade. The Philadelphia Mint received an order for 50 bronze medals for the 1928 Assay Commission meeting on February 3 of that year, which it filled on February 10.