Manufacturer's Faults
If there is damage or other problem with your car which is due to a manufacturing or design fault, then this issue is between you and the dealership, and it is your responsibility to deal with any issue before you return the car to the lease company, and preferably at the point when you notice the fault.
Manufacturing and design faults are not so very uncommon and can include such things as corrosion and tarnishing of exterior trim and fittings, paint or coatings peeling or falling off, or things falling appart because of poor manufacture or assembly.
If you have an issue which you believe to be due to poor manufacture, it is often worth doing some research to find out. There are websites such as www.peachorlemon.com where people report problems. You can also post on the messageboards and forums of car sites, enthusiast forums and consumer guides, you should quickly hear if other have had the same problem. Otherwise, call a few dealerships to ask them if they are aware of the problem before approaching your own dealership. Getting a dealership to 'openly' admit a manufacturing fault can often be tricky.