I have one with stripped threads, got a new old stock part to replace it , I tucked them away and ended up using a Bassett, if I can find it and replace the worn part I'll let it go cheap.
I did locate the mount, its not plain like the one pictured but has 2888-89059 plus Hebrew letters, running vertically perhaps a rifle serial number 415515, still looking for the new mount lever/screw, I have the stripped one.