Saw bladed bayonets were only issued to pioneers to my knowledge. Following the 'Rape of Belgium', in which the Germans murdered over 5000 Belgian civilians and torched settlements in the path of their invasion, lurid stories spread largely in the gutter press of German soldiers sawing off babies hands and women's breasts with their bayonets. Tim Cook and Niall Ferguson have both written about the difficulties inherent in surrender and prisoner taking in the First World War, and it's stories like that conjured by Remarque that were part of this. Filling eyes with sawdust is undoubtedly embellishment, while it's probably untrue that such a relatively uncommon bayonet would be cause for the murder of a prisoner.