Agree 100%

First, Kurz actions are all small ring (except one identified in Speed’s book)
Also, look at the thumb cut in the left wall, it is almost as long as the rest of the wall - about half the length of the left side of the action wall.
The floor plate release lever is more than half the length of the floor plate.
These things are the most obvious visual features that are easy to differentiate a Kurz from a standard length action.