Alex,
Thank you so much for this information. If they are really even close to that old, i will probably leave them as they are, maybe very careful and mild cleaning to remove the rust. In no case i think they ain't gonna end up to be my everyday shavers.
Finding these 3 razors from the local flea market was maybe something that isn't happen too often. I think i gonna get back there and take a deeper and closer look for the rest of the razors.