This type of mount is going back on the "Gewehrfabrik Danzig" and was used to built up sniper rifles in WW1. So it is also known as " Danzig mount".
In 1919 the optical firm Görz (Goerz)Berlin was the holder of the austrian patent Nr. 86021 which shows an mount with the same front base.

The interesting point on this mount is the fact that the front base builts an pivot point for the side correction. So there is very little twisting in the scope as by other early scope mount types.