it sounds like you are describing one of the kreighoff presentation lugers. krieghoff inc. engraved and silver inlaid several lugers which were given as gifts to high ranking german leaders from 1935 till 1944. if you find one in your grandad's closet it is worth 100-200,000 dollars. i could very much expect there is one as you described with himmler's initials on it. Georg Luger did have a son also name georg but there are no records of georg francis having been active in the family business. he would have been in his sixties by the time of WWII.