Gebrüder Luck hung out their gunmaking shingle in 1879 and in addition to guns, they made Bicycles to meet the Bicycle Craze of the late 1800s. The frame and spark arrestors, whatever, near the strikers date to a much older period that WWI. I would say they were burning thru inventory during WWI trying just to meet orders.

Serbus,

Raimey
rse