In this site search for "KG 13" more pictures of several variations, KG-13A, KG-13B, KG-13C, versions with autopilot switch..
https://www.deutscheluftwaffe.de/?s=kg+13
3D files created with drawings on "Knuppelgriff KG-12.pdf" manual - attached.
https://grabcad.com/library/kg-13-flight-control-grip-1
Time ago this guy in DCS World forum sell files for 3D printer: [FOR SALE] KG13 Luftwaffe grip STL for 3d printing
Pictures from Russian collector...
This grip seems similar to the Dunlop used in Hawker Hunter of 1950's, just with French labels for fire buttons covers, maybe for Swiss exported Hunter's.
https://picclick.co.uk/Hawker-Hunter-Pilots-Control-Stick-Grip-Part-No-143628224948.html#&gid=1&pid=1
Seems more this version, but with...