Right, it's just two metal surfaces mating to each other. I did do a very light sanding with 320 paper over both surfaces and I still get some water into the inner tank. The surface on the valve body seems to be flat. The surface on the flapper looks to have a raised round lip that, I guess, is to seal against, or nest into, the flat surface on the body. A little surprised that this was intended to form a tight seal, but it is 1920's technology. Asking if these are reproduced was a shot in the dark. Am thinking to have someone who refurbishes these, like Tim Long in PA, to just take it and see if he could improve it. Thanks