Unmarked insert. Wheel has non-diagonal ridges, and wheel rivet may be damaged/repaired. The cam stop is a U-shaped piece of sheet brass that is soldered inside the lid, not part of the hinge, as found from 1940 on. Internal 4-barrel hinge. Lighter is slightly shorter than later models, and has very square vertical edges.
This is a Type 10(C?) 1938-1939 Model, in "Zippo: The Great American Lighter Including the Poore Guide to Zippo Prices".
U.S.S. Edwards was a Clemson-class destroyer, DD-265, originally commissioned in 1919. It was transferred to the Royal Navy in 1940 with 49 other destroyers as part of the Destroyers-for-bases deal. "CMF" is likely an officer or crew member before the decomissioning and delivery to the Royal Navy on 8 October, 1940.
Both sides were initially filled with black enamel, though up to one half is now missing.