Most of you guys know that I am a serious collector of Kaywoodie pipes but don't consider myself an expert. Yes, there are some of us that have paid in excess of $500. for a single Kaywoodie pipe but they are usually the antique, cased, extra large handmade pipes from the 1920's and 1930's or earlier.
As for Al's photo of the above mentioned Kaywoodie. It would date to the 1930's or late 1920's. I have enclosed a couple photos of some experimental Kaywoodie's that I have in my collection, one of which has the identical stem/button as the one shown. This stem was purely experimental and I never have known it to be put into production. A pretty rare piece IMO and some lucky collector should be pleased to own.
Here are the photos of 2 different experimental stems. One is a very early push tenon, the other with a screw tenon.
Sorry, Photobucket seems to be down, can't get the photos uploaded???
The stem on the pipe in above photo is called "Experimental Kaywoodie Right Hand Bit".