K.B.A.G =Kreigs Beckleidungs Amt Garde
GLJR1= Garde Landwehr infantry Regiment one
There is a limited explanation of these at
http://www.pickelhauben.net/articles/DepotMarks.htm
With that aside, this helmet raises my eyebrows. The Garde Landwehr Regiment never mobilized. Apparently it was too hard to do with soldiers coming from all over the Empire. So why is there a filz helmet? Possible yes -- maybe I'm just paranoid but I have seen a lot of fake markings recently. Where is this helmet from?
My understanding is that Garde-Landwehr-Fussartillerie and Garde Landwehr-Pionier-Kompanie were on the army strengh in 1914 as the haube does not seem to be issued I can only assume it was a stores pick up after the war and given to the museum, my thought on the stamp is why have one on a regiment that was not formed?