I would certainly send an email to Leica archives with your camera and lens serial numbers and ask for any historical information they have. I did this for a Leica IIIc I just brought and they advised that it was produced in 1949 and delivered to an address in Germany in September 1949 but had no further information. Sometimes they can advise if and when the camera/lens had been returned for rapair or service. They will reply within 1-2 weeks.
As for haze in the Summitar, that is very common and is easily cleaned particually as the lens is uncoated. Early coated Summitars are noted for having very soft coatings and are easily scratched. My 1953 coated Summitar looks like someone cleaned it with sandpaper, but is still usable.