KW also made Praktinas and I would have thought they would have been a good candidate, having interchangeable viewfinders... But haven't seen that one in any list of Praktina prisms either...
Who made the Pentacon Super? Maybe it fit that...
M6, SL, SL2, R5, P6x7, SL3003, SL35-E, F, F2, FM, FE-2, Varex IIa
Praktika made the Pentacon Super long after the KW brand had evolved and changed name but its roots are KW. KW also made the Pentacon 6 which was original known as a Praktisix.
This prism was exported to the US who insisted on the "Germany, USSR Occupied" marking.
The story of KW and John & Charles Noble is quite interesting, the company was very innovative making the first 35mm (full) system cameras, Exacta's never had motor drives and bulk backs.
The eye-cup fit is the same as the later Prakticamat and Nova, etc, cameras.
My APUG portfolio