Barbers Chair Foot Plate

I'm looking for more information on this foot plate. The name on it is Koken Barbers Supply Co. - St. Louis. I believe it's a bottom foot plate from a chair the called the Congress. This design of barber's chair was patented on October 30, 1888. I'm trying find out what year this plate is from. I have seen different mounting hole locations. The plate has the word PATENT at the top separated in the middle by a mounting hole.