Need more help with buying a motocross bike!!?

[Matt B]

Ok so I have an opertunity to buy a used race bike but I heard that you shouldn't buy a race bike? The bike is a 2009 kx450f. I am a B rider and the guy who raced this bike was an A it was the race bike not the practice oil and air filter changed after every race. It is being sold at a dealer a shop called g force powersports they told me that they do a 21 point inspection before they even try to sell it and replace anything it needs! I need to know if I should do it or not?! Please help a dude out. Thanks, Matt