If it has the original bar... Look at the paint wear. It will be very telltale of the amount and type of use. Also look at the chain, if it's dull as all get-out, you can assume the old guy ran it that way--which is hard on a saw. Why is it hard on a saw? A dull chain overworks the saw by keeping it in the highest rpm range. It's like standing there with the saw at WOT (wide open throttle), and holding it there for an extended period of time. Heck, that's not good on any engine.
Look for signs of misuse, like cracks or dents. If it's in the kind of condition the dealer is saying it's in... I'd pick it up today.