The rifle is marked on the top of the receiver;
Waffenfabrik Mauser A-G Oberndorf A/N
The Model 1922 had the Sauer assembly number on the buttplate; usually a 5 digit number in the late 20,000 range. The Made in Germany.....marks were on the Model 1922.
The serial number is the Mauser number and Niedner was not involved with this rifle.
The Mauser caliber on the side of the receiver is 6,5 and after the serial number "P.P." for Portugese Patrone which is
6.5x58.

LSW