The best available information indicates that, in this case, the blade blanks were produced by Gottlieb Hammesfahr and sent to Schubert u. Salzer Maschinenfabrik for finishing. M98/05 bayonets with a Schubert u.Salzer Maschinengfabrik making have only been recorded with dates of 1917 and 1918.
See German Bayonets, The Models 98/02 and 98/05 by Anthony Carter, page 86.
Reservist1