First, I wouldn't trust that gauge as more than just an indicator, it might be out of calibration even if it is new,
Second. If you have had it running under certain conditions, idle or highway, that might be expected. I believe that fairlanes rarely got shrouds if they didn't have a/c, but under that type of weather conditions, I would consider trying to add one or, if you aren't trying for concours, I would personally upgrade the radiator or fan if it will be driven in those conditions often.