Here helmet with the same fastening.
https://www.history-shop.de/katalog/artikel/Bayern_Pickelhaube_eines_Offiziers_54364_e.html" onclick="window.open(this.href);return false;
Vulcanfiber helmet was produced after 1916, last wartime. Can for reduction in price have put a NCO or EM wappen?
In books J.A, Bowman and T. Cowan too there is a photos of officer helmets with only central crown pierced...