Thanks for the information gentlemen. The overstamp on the second Dunhill threw me but what dmcmtk wrote makes perfect sense. Re: Orlando's response on the tenon, I think that is very plausible. I did not know if the tenon had anything to do with the particular patent that was pending. Does anyone know anything about the number on the bottom of the bowl? The Big Ben is a well made little pipe and smokes great. Thanks again.