There’s nothing odd about this photo until one looks a bit closer at the machineguns lined up on the ground. While the one furtherst from the camera is clearly an MG 34, the two other are wooden mock-ups. It’s my guess that the photo is taken in 1935 or 1936, right after the Wehrmacht began to expand. When the Treaty of Versailles was renounced in 1935, the Army grew from the allowed 100,000 men to some 300,000 in one big leap. Germany had been hobbled by the Treaty, which prohibited weapons like tanks, and placed a cap on the maximum number of machineguns that the Germans were allowed to have. It was set at less than 2,000 machineguns (756 heavy and 1,134 light MGs) for the whole Army, and it took time to equip all the new units. So it seems like wooden “weapons” were used for training purposes during the first year or so of the newly-minted Wehrmacht. Soon every infantry squad in the Army had its own new MG, and the mock-ups could be turned into firewood.