I am an amateur texture artist working for mod projects in my spare time. Currently I am the lead developer of “The Great War 1918” team, a WW1 modification for Company of Heroes (as texture artist, historian, designer and code monkey). I also assist the Verdun Online project as historian, an indie FPS game project set in WW1. Amongst other projects I made textures for "His Righteous Mod" (under the nick Grenadier), a modification for Dawn of War.
Model 1915 Adrian helmet.
It has the darker finish of 1916+ cooked paint, a method used to avoid reflections (as in the glossier 1915 models). The leather strap not original.
The grenade badge was used by metropolitan (i.e. not North African or colonial) infantry and cavalry (with the exception of Chasseurs à Pieds), and by the Foreign Legion.
Trivia: it was very handy when I did the skin for the TGW1918's Adrian model ;)
(part of my collection)
It was used also by the Italian Army, but I cannot see differences between the French and the Italian one.
The Italian version was made of two parts instead of four. Also the badge at the front was stencilled rather that being an actual moulded badge.
The Adrian was also used by the Belgians, Russians, Serbs, Poles and Romanians.