Restore a parkerized luger?

If it is a byf 42 model in the m serial number range it could be a parkerized Portuguese model. They ran a lot of the Lugers through a rebuild program. I also have a 42 1939 model which has a pakerized type finish which was my first Luger purchase. It has a deep dark blackish color to it. We need to know the markings on the Luger.