The 1926 has the lange vizier type sight like the GEW98 had and the 1930 has the vernier sight.
The stock on the 1930 version has 2 cross bolts that the 1926 doesn't.
You can't see it in this picture but the little floorplate release lever inside the trigger guard has the last 3 digits of the serial number. The bolt in the '26 is mismatched and the one in the '30 is unnumbered.
I think I have found a '95 carbine front band/nose cap, if I do aquire it I will have the '26's barrel cut back to 17" and recrowned.