I knew a guy who bought a brand new bike, parked it in his garage and NEVER rode it.
There are a lot of people who get introduced to dirt bikes, go out and buy one and then shortly discover that they don't have the time, the money, the opportunity, or simply the skill to ride.
There there are people like me, who routinely put 10 hours on a dirt bike on a weekend, at least once a month. And then there are people who ride several hours a day!
So it is impossible to say if that is a reasonable amount or not. Like Joe said, if that is true then everything on the bike should agree. I wouldn't pay extra for low hours. Sitting, unused, not getting lubricated is not necessarialy a good thing.
Rod