What you didn't get at that great price is the 12 month factory warranty*. I purchased a new 'O8 half way through '09 for 7300. I noticed the rear wheel powder coating was blotchy and mentioned it to my dealer on first service. Because I had the new bike factory warranty, the dealer ordered my up a new rear wheel and tire - parts and labor were free.
I agree you got a great deal on your bike and if you have the service records ( and because Yamahas are well made) you'll probably be OK. However, there is some value in the insurance factor of a warranty.
*of course, if your seller purchased an extended 4 yr. warranty before he sold you the bike, you're golden!