Reportedly ten thousand delivered to the US military, many of which ended up as war surplus and sold to civilians. This one doesn't have 'US Army' marking on the back.
. . . but they're truly rare. The 2179s produced for our Army (as chronometers, yet) weren't the only versions made; there were earlier models, initially intended for the civilian market. These have case stampings of 2179 without a /1, or higher, suffix.
One of these would be worth searching out. Black dial, gilt leaf hands, if I recall correctly.