It depends. Theory of an engine is that valve life determines a lot and the design of the valves is a big factor. I have not seen the setup of the valves for the 450 but w/a dual overhead cam setup I can tell you that 10hrs or less is a little extreme.
In 10hrs your valves should not be too much past the basic seating position. I know C'Dale had like a every 50hrs and I went 330hrs or so w/out adjusting them at all. Of course they were gone when it came to a rebuild but they worked fine. Probably should've been adjusted around 100hrs or so but think of this. When you do a rebuild or after a couple hundred hours, don't most people/dealer switch out for new valves anyway? They are cheap and usually costs less to replace than for a dealer to repair them.
I say when someone gets like 25hrs on one to then check their valves and tell the rest of us w/photos.
I'd do it but I ONLY ride tracks so get like 4-8hrs a month on it at the moment. Granted track riding is a pain on an engine, but it'll take me awhile to get there. If no one does then I'll pop mine out in a month or so just for kicks and check them out. Maybe see what can be done to boost the power w/lighter springs or something anyway.