There are swastika inspectors' marks on my 1936 Eagle Radom 9mm pistol as well.
As was pointed out in an earlier post, the swastika is a very ancient symbol going back to at least the Indo-European cultures of central and south Asia. It was also used by early Native Americans. (Which makes sense, since the general concensus is that humans migrated out of Africa, into central Asia, then westward into Europe and eastward into the far east and over the Bering Straits land bridge into North America.)
I have even seen it in decorative carvings on pews in Catholic churches.