G'day Grob, Check the area where your racket shaft joins the handle. There should be 2 sets of laser etched serial numbers, one on shaft and one on the handle cone. Older Yonex rackets will have indented serial number on the cone though.
beats me, I can't find nothing ! If I see you on the weekend Ill let you take a look at it. But what I said in my PM still stands.