I continue :
---The Feld-Artillery was the hypomobile artillery in 14, which accompanied the line infantry.
--- Foot artillery was heavy artillery, siege artillery, fortress artillery, or rail-mounted naval artillery. Position artillery was much less mobile.
--- Given the above:
In theory :
--- There were 84 field artillery regiments with no air flaps on the rear spine (and bulging scales on the jugular).
---There were 17 Artillery-Regiment on foot with ventilation flap on the column (and flat scales on the jugular)
Frontenac
Nice helmet.
But, Fiel-Artillerie 64, regulations should have the rear spine without an aerator. My Saxon foot artillery helmet N°12 (METZ garrison in the Reichsland) for example is correct.
This anomaly is explained once again by an emergency assembly of the mobilization where the regulatory standard was no longer respected given the circumstances and the urgency. This is how (as Sandy says) your helmet no longer has the small format side visor rivets, but the rivet heads normally used for attaching the base of the visor.