Koken Dentist Chair

I have not seen another one like this in the few years I ahve had it. Isaw the chair and fell in love with it. Wife saw it and hates it. I dont know when it was made or if Koken has a model # for their chairs. It is cast iron covered with porcelain. It has a hydrolic base but the oil was removed when it was moved so it woudl not leak all over the place. I never tried to refill it since it is in my game room and dont want to find out it leaks while in the house. the head rest is covered in leather and looks to be the original leather. I cant be sure but it sure looks original. Any info I can get on this woudl be helpful.