Never heard of one. Why you asking?
most of the very old ballcock assy had replaceable seats...shut off water ..take apart the top where float are hooks up to there should be rubber disk seat ... you may be able to install fluidmaster to replace it ...sorryyour answers are important .the toilet is in long island ny it is a old toilet,an the flush handle will flush in 2 direction .everything inside the is made of brass .it does have a ball float w/set screw.the problem is the water keeps running .i never seen one like this.