You can see the reproduction in zoom from Britannica article. There is an original part of the 17th century work i.e.  label saying  N COPERNIC under the portrait. Scientifically it is a copy of 16th century self-portrait. Under this zoom is the adequate Britannica comment. My advice is if you want know more about this historical item you should contact directly the Museum of Jagielonian University.74.213.188.138