I am thinking about buying a used walk behind mower from a very small dealer of used equipment. It is an exmark viking hydro with 500 hours on the meter for a very good price, in the 1500 range. It has a digital meter that is working. What worries me is that the rear tires are bald. They have another mower like this with around 500 hours and bald rear tires. My boss's scag has about 500 and the tires are nowhere near bald. This amount of wear seems unusual along with the cheap price, and I suspect the hour meter may have been tampered with. What do you think? Is this amount of wear unusual?