I think there is a discrepancy on the Getzen website. On the Genesis page, at the top it says .462" bore. But in the description at the bottom it says it has a .464" valve set. I don't know much, so I may be wrong, but shouldn't those numbers match? Perhaps someone could explain what "Bore" really means? When someone says a horn is .459", where on the instrument does that measurement come from? Could a horn have 2 different bore sizes?