I am not sure about this, but I believe the Nuovo Racing is a tre tubi frame, with a double-butted Columbus main triangle and seamed CrMo forks and stays. To me the real question is whether we are seeing rust seeping out from the inner surface of the tube, or whether this is just a localized corrosion problem. I think you can ride it safely enough, but pay close attention to any emerging squeaks or play in the rear triangle.