I believe the rotor has a minimum thickness stamp in it so one would suspect it could be turned, but have not heard of anyone doing so. I wouldn't worry too much about it unless you get bad pulsating feedback through the lever or the notorious 'warped rotor bounce' at braking. If it locked up I think yours would be the first. I (and a few others) had a rotor that was severely warped. Front end porpoised badly especially at low speed braking. The shop guy put a dial indicator on it and it was obviously out of whatever spec they use so it was replaced under warranty. If it doesn't bother you on the road, keep and eye on it. If it gets bad enough to affect your ride, take it to the shop.
