I have a question:
Are the underside of the visor and neck cover green and red or light brown?
I have another reading than the friends above:
---In view of the “Portepee” roundels, (for Feldwebel for example), this is a non-regulation Eigentum helmet (commercial purchase). Only the fittings exclusive to officers, and forbidden to Portepees, differentiate this helmet from an officer's: the cockades and stars.
The silver color of the tip rivets is consistent with a Pioneer “non-officer” (white-silver).
Pioneer officer stars, on the other hand, should be yellow-gold.)
---I'm not shocked by the difference in patina between the front eagle and the other trimmings. Officer's eagles were always given an anti-patina treatment:
-Nickel silver was silver plated, nickel plated or coated with “Berlin white”.
-Brass was gilded.
In fact, this can even be seen on the regulation spiked helmets supplied by the B.A. when the helmets have not been excessively polished with abrasive products.
As far as I'm concerned, a fine, privately purchased helmet, my helmet is reserved for outings, and is not to be worn in garrison.
Infra, a Saxon Extra-Helm, for non-officers. These helmets could be mixed and matched with elements for officer's helmets: silk cap, officer's read spine, visor trim, openwork crown, Perlring, M71 chinstrap with scales, etc...
These helmets could be worn by a chief Musikmeister, a Fähnrich, a Juncker, an Einjährig-Freiwilliger, military medical personnel (vet's assistant, dentist, etc.)...
View attachment 49511
En comparaison avec un casque de Général :
View attachment 49512
Concerning the treatment of front plates, Here's a Kammer helmet, in its original state, never polished. The gold plate has not oxidized like the other brass fittings. :
View attachment 49513
As on French forums, I say...and I show.

My conclusion:
Nice Extra-Helm Eigentum “fantasy”, non-regulation, from a Uffz-Portepee, from Reserve of Pionnier