One way to get a indication of the weapon these were designed for, it to look at the maximum range indicated on the sight; then compare to all the 9cm guns in Austro-Hungarian service. Can you give the maximum range on the sight?
These appear to be sights for the Austro-Hungarian 9cm M75 field gun. There are good detailed photos in Artyleria austro-węgierska w latach 1860-1890 by Łukasz Chrzanowski printed in 2008, on pages 71, and 77 of sights of this type.