The Erfurt and Danzig stocks have the "normal" checkpiece.
The interesting point is that it is definetely not an later conversion, this are the only rifles that ever made in german state firms for the comercial market, also it is definetely dated between 1918-1919. (All state factorys where closed at end of 1919)
You must remember that it was forbidden in 1918 to own military rifles for civilians, so the stocks and the systems were clearly signed to get no problem with this. Also this rifle is chambered in original 8x57 IS, treaty of versaille was later and this one survived to be chambered in 8x60.
There where no extras that could be orderd, only this type, no other chambering, no other stock, no engraving.