Exa/Exakta Mount Registration
I haven't had an Exakta for some time. When I did it was a VX 500 with a 50/2 Zeiss Pancolar zebra lens. The lens was reasonably sharp. I think it was one of the better standard lenses in Exakta mount at the time it was made. One of the problems for me was that there was always a little play in the mount when the lens was attached. I ever got the feeling that the mount was as tight as that of a Canon FD or Minolta SLR camera. I still have one lens which is in an Exakta type mount. It's a 105/4 Noflexar bellows lens in Topcon mount. I used it mostly with an adapter on a third party bellows in Konica AR mount. The camera was an FT-1 with a Nikon E screen (grid type) installed. If I did not already have so many other macro lenses in Canon mount I might try using adapters to use the Noflexar on a Canon bellows.
Back to the original question, from what I have seen most of the Exakta mount lenses fit most Exakta cameras. Whether you are happy with the exact fit is anlther question.