I recently purchased A Koken chair with a round seat and all porcelin handles, the seat does not raise yet but the seals have been replaced and I will be replacing the fluid in it just as soon as I move it to its final resting place. I know very little about this chair and the serial # or tag under the seat has been removed. Is there any other way to determine the age of the chair or find any other type of identifying information. I plan to keep and would like to fully restore the chair back to original possible so any links that you can tell me would be helpful and I can post pics as well