For me, the manufacturer's stamp, the side vent, and the grain of the leather visible on the inside lead me to believe that this is a traditional post-war shako, used for veterans' ceremonies. Officer's spiked helmets, colbacks, and other traditional military headgear were reproduced between 1920 and 1930 almost identically for veterans and honor guards. I prefer this Shako, infra, without a Schupo-type vent.
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Similarly, the Guard's mitres have been remade by the same manufacturers as before the war. They look similar, but you have to look closely at certain details. The same goes for the colbacks.
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