Well this is a parts find on ebay. I do not know the background on these lenses. I have never seen a corrosion hole on a camera shutter before, so my thoughts are that it was in someone's basement and their basement flooded. That would explain the fungus on the lenses, and the seepage marks on the outer body. It make sense the corrosion. There was other corrosion on the some of the other blades but I cleaned them up. I think this shutter will be a complete teardown. I might even give my friend my own nice 90mm and just use these myself for fun. No sense in sending her possible junk. If there is fungus, I will treat the whole lens in the solution and rebuild it. It's like a giant jigsaw puzzle. Plus I have the Mamiya Parts manual, so it won't be as tough as it would be having nothing to refer to like normal.
The greatest thing is that the Mamiya Seiko shutters are huge compared to the Agfa shutters I do regularly.