I believe that is the correct bayonet for the K31 Swiss
the saw back bayonet was something that was around from before WW1
Sawback bayonets were something the Engineer battalions were issued, so these guy would have a saw. However when WW1 kicked off, the Allies demonized the Germans to an incredible degree, and in their propaganda claimed the saw teeth were there to cause a more severe wound as the bayonet was withdrawn. As if getting bayoneted was survivable. This WW1 war crime hysteria against the Germans resulted in captured Germans being shot on the spot if they had a sawback bayonet. An original German sawback with its teeth is rare, as the Germans ground the teeth off, to avoid summary execution. I have a German sawback sent as aid to the Turks, and the teeth were ground off.
I really don't know if sawbacks were made after WW1, the saw function was not very good, and then your troops might be shot on the spot if captured.
No one seems to have liked the spike bayonet.
Sure it was lightweight, and it was cheap, (of no concern to anyone but Ordnance) but the thing was, it was useless to cook with, to chop, to cut roots as you dug your foxhole, or to pound with. Bayonet butts got used as hammers.
The Martini Henry and a bayonet are an outstanding combination.
You put a socket bayonet on a Martini Henry, and you will start looking for things to stick with it. The rifle and bayonet are so well balanced, and your reach with a fixed bayonet just gives a person confidence.