it is the firing pin.
it appears to be a military version as there is no safety sear.
very cool..not to sure but I believe 1916 was the last year for Eufert.
I have a 1914 Eufert #'s correct, the Mag's should have the same # as the gun along with those #1 and #2 . a replacement firing pin shouldn't be to hard to find, but I'd make sure to keep the old one as it is also numbered to the gun.