I wasn’t going to weigh in on this, since it generally should have been asked on a gun forum. Internal marks on pistols and other firearms are usually indications of sub-assembly inspection during production. What mark was used for each inspection (inspector) are facts usually only known to the factory that made the firearms, and often then not generally after many years have passed, due to reassignment, retirement, etc. of inspectors. As to the marks themselfs, they often simply represent a die stamp with some symbol that was not in use at the time the inspector was assigned his duties, so it was issue to them and recorded to be their stamp. I suppose in some cases the stamp itself could have some meaning, but often it has NO meaning other than to identify the specific inspector who perform a specific inspection that called for his mark to be placed in a specific location on whatever he was inspecting.
I recall that years ago, a well know journal on a specific type of firearms degenerated into endless questions and guesses about the meaning of internal marks on Lugers. That specific journal is much better today.
As collectors, sometimes we read too much into small factory stamps, the precise meaning of which are known to almost no one and again, generally represent simply a “manufacturing in progress” inspecition of a specific finished (or stage of production) part.