Good Eye Marshallj, I missed that.

Yes you did and I even commented on it.  My bad.      

These "Extraseitengewehr" were private purchase items of extra quality and not generally items of issue.  It is not uncommon that the press button in the pommel does not function as they do not ordinarily actually attach to the rifle.   Often the slot in the Pommel has a colored felt plug.      These private purchase bayonets were marketed as short KS98 for NCOs and longer KS98 for EM.  Mostly a marketing strategy by Eickhorn and other makers.  Here is an example of an interesting Extraseitengewehr made as a modified S84/98 bayonet for an Enlisted Man.  This bayonet has an extended guard (like on your KS98), ribbed plastic grips, a flash guard, and a longer blade.  Notice the proper S84/98 frog and the Regimental Staff Portepee {Stabe I).         

Posted one in Post #17

A very neat photo!  I have never seen a Field Rabbi photo before.  

Field Rabbi Dr. Aaron Tänzer near the front in 1917, the Russian Front that is, Iron Cross 2nd Class we see. Tänzer educated  at the Pressburg Yeshiva then on to  University of Berlin,  was actually an Austrian believe or not, he just happened to be residing in Germany as a appointed Rabbi in Göppingen  when the war started, this in Württemberg, apparently applies to go into the German Army rather than returning home to Austria to join the Habsburg Army, I guess requesting permission to do so, maybe even petitioning the King of Württemberg himself. After the was he doesn't go back to Austria but back to Germany.   He has his own WIKI.  https://en.wikipedia.org/wiki/Aaron_Tänzer

I made pdfs of the old Diana's Buttons page from angelfire that I got on the wayback machine. I'll post them here.    Diana's Buttons - Reference - British Navy Buttons page 1.pdfDiana's Buttons - Reference - British Navy Buttons page 2.pdfDiana's Buttons - British Button Backmarks.pdfDiana's Buttons Article - Crowns and Cyphers on British Uniform Buttons.pdf

Based on the notebook I am guessing he is Der Spiess.

Wow.  Rich A. in Pa.

Thank you for your reply:)) I had considered that, but in German there is a term "Extraseitengewehr" which means, that the bayonet is an extra to the one used and to be worn for parades. Usually, they don't have the push button for mounting it, but sometimes they do. So I was never sure, which one it is... Could you gibe me some insight as to why it is an NCO's?

Got mysellf a new QMD!