and was still working
the old man who lived there said it was 35 y/o....I don't believe that but I have never seen one in this bad of shape that was still working....
Have an old (AmStd low-boy one piece) at a cabin I winterize, has the old brass soup can. I have yet to need to get at the flapper, but I'm guessing its a douglas tank ball under there.
That particular toilet also has a petcock in the bottom of the tank for draining.