1938 Kohler toilet wall mounted tank

I have a 1938 K6798 wall mounted tank for a toilet. I bought several new parts. $ 90.00 worth. It still leaks between the ringnut at the outside bottom of the tank ant the surface of the tank. I oriented the new gasket so that it is inside the tank and the bevel is in contact with the ceramic surface of the hole. In other words the bevel points outward. I did not see any gasket on the outside or the tank at the ringnut.I cleaned this brass fixture before istalling the new gasket. I did not see any cracks. I bought a new el $30 and a fixture/fitting that goes into the bowl. None of these appear to be leaking.