If you have taken good care of the vehicle, it has no noticeable chips, stains, scratches, etc., then one of the other people commenting is correct that the dealer has little reason or motivation to negotiate too much with you, especially if the vehicle is well below the allowed mileage. They are likely going to be able to sell it at a premium any, regardless of whether it's to you or to someone else.
That being said, the answer is already "no" if you don't try, so you don't stand to lose anything by asking for a better price. If you're somehow stuck on the idea that your price has to be anywhere near KBB's valuation, that's just not going to happen. There is so much subjectivity on how those numbers are arrived at to begin with. KBB is a good resource as a baseline idea for a price, but you're never going to get a KBB valuation on a used car.
Remember that the dealer will be going over the car with a fine-toothed comb when you take it in, and the person doing it is trained to find any little thing they can that is to their advantage in negotiating with you (or, even worse, assessing extras you have to pay for that were not part of normal wear and tear in your lease).
Auto negotiations are not fair, simply because you're up against people who do this for a living, and a dollar to your advantage is a dollar to their disadvantage, so they will use everything they can to get the best deal for themselves.