KMZ turret viewfinder prism

I have a KMZ universal turret viewfinder in which the outer prism was badly damaged before I got it, (big chips out of the glass, presumably dropped onto a hard floor). The other smaller prism is not too bad. Would anyone have a spare outer, (long prism nearest to the eyepiece with the roof shape), that you could let me have, from an old scrap viewfinder perhaps, please? I think that there is supposed to be some sort of separator or retaining ring as well?