I see nothing that indicates any Masonic connection what so ever. I've carefully checked my pubs on Masonic Symbolism to try to be as accurate as I can be in saying this. Perhaps a Brother much more knowlegable of symbolism will step forward and correct me!
In Masonry, and this goes back to the period that this pistol was built, and includes all of the area now considered to be Germany, a masonic symbolized star would have FIVE points alluding to the five points of Fellowship, or summary of a Mason's duty to a Brother master Mason. Note that the stars shown on this pistol have more than five.
The seven stars and half moon symbol seen on this pistol go far, far back into antiquity and has mixed meanings, and may be tied to Diana, Goddess of the hunt. The number "seven" is and has been sacred all the way back to Noah receiving "seven days notice of the flood", selecting clean beasts by sevens (not pairs!), 7 persons with him on the ark, etc, etc, seven ancient planets, seven alters burnt continuously before the god Mithras, and the list or examples goes on and on
This is my opinion....a 32nd Degree Scottish Rite Mason, but please know that I may be wrong and could be corrected by a Brother Master Mason more knowlegable in symbolism than I!