If I were leasing a vehicle I would not touch it. It should be warranted for the duration of the lease. And routine maintenance like oil change really does not save you anything and if a dealer manages to screw this up it is on them. A dealer (let alone indy shop) is not required to report service to CarFax, so there is that. If you are still worried, I would think if someone never changed oil for close to 3 years that would show somehow. Like sludge at the bottom of the oil pan. Or something. Find a mechanic for pre-purchase inspection and ask them if they can tell if the oil has been changed regularly on the car. My bet that it has been.