If you can prove the car hasnt had any paint work done then it should be coverd. The emphisis is on SEAT proving that it has. If it hasnt and has standard wheels, suspension etc. Ie nothing that could be atributed to damaging the paint then it should be under warranty.
Aimez is one person I know who got hers done and that isnt even a standard car. So its worth pushing it further. Im sure others have managed as well.
If its a front wing btw I would just replace it, I did with mine and the new panel is now rusting. Mainly due to the wheel catching the arch liner sometimes and rubbing the paint.