To find your colour code look on the vin plate and it will be the 2nd square up on the left hand side.your tailgate has rusted because the chrome trim cuts into the paint ,best thing to do is rub rust right out ,prime it, base coat it then laquer it,and when you put trim back on ,put a plastic washers on the bolts that go thro tailgate and this will just keep it off tailgate and stop it vibrating and cutting into new paintwork,hope this helps.