1939 New York Worlds Fair. Lincoln Gold Dollar. HK-493a, DeLorey-49, Cunningham 10-400X, var. Rarity-5. Gold. MS-64 (NGC).15 mm. Satiny medium gold surfaces. The 2015 Cunningham reference on Lincolniana incorrectly assigns HK-493a to Cunningham 10-390S, which is a 1927-dated version of this piece overstruck on a 1924 Mercury dime. Cunningham 10-400X is the correct description for HK-493a, but refers only to the Matte variant HK-493. The Brilliant HK-493a is actually unlisted in the Cunningham reference.