cptbob said:that stamp on the backside of the liner flap. It appears to say B.5.A.1. 1918 and then I. (or L maybe, the ink is a little runny).
Just look closer! :wink:
Stamp is: K.B.A.G 1918 f. (Kriegsbekleidungsamt der Garde, 1918, feldbrauchbar = service able). The date could also be 1915 or 1916!