This is a particularly interesting helmet for a number of reasons. It is dated 1905, and was clearly adapted to an M15 cruciform top. It does not have M91 lugs on the side. This makes sense if only the top has changed to accommodate no spike. it is standard Bavarian officer. It has round chin scales. You can see how the spike unscrews. There seem to be a number of Bavarian helmets like this. Iit is not clear to me why the top would be adapted, but not the chin scales. The Prussian AKO does not mention the chin scales, but only the top. So perhaps the Bavarian order was similar?

Most officer helmets are unmarked. It seems as if the owner of this helmet had a fetish for marking his helmet. The name W. Fhrh. von Ebner is all over this helmet. In pencil, and in a purple ink stamp. Glenn Jewison sent this research:

"The only "W" I can find serving in 1905 is one Hauptmann Wolfram Freiherr Ebner von Eschenbach who was an artillery officer. Born in 1871 he was in the 3. Feld-Artillerie-Regiment Prinz Leopold.

Sekonde-Lieutenant: 20.05.92
Oberleutnant: 24.10.00
Hauptmann: 13.12.04

By 1914 he was "at disposal" status and serving as a librarian at the Bavarian Army Library and probably remained there throughout the war."

Is this the guy???