I work at a Mazda dealer and sometimes we put on a chrome fuel door just to give a car more of a look. But if a customer is interested in buying the vehicle and wants the original fuel door, we put it back on the car. The dealership should have given you your original fuel door. If they didn't, go back and talk to them about your situation. On the positive side, the fuel doors are not hard to remove/install. Just pop open your fuel door as if you were going to put gas in your car and take a look. I believe there are two bolts holding the fuel door on the car.