Alan, Thanks for the clarification on the use of the term "channel" I could not recall the wording when I got to the computer.
Along your line of thought Jim, perhaps Pender had no definitive source but speculated that the absence of a army proof meant a commercial source (he lacked your extensive database and the precise understanding of when the first Army HSc appeared). A plausible theory when you think that the initial HSc (LGSs) were primarily KM with some commercials - army markings came later. So perhaps initially there were only unproofed "commercial" units of which some were obtained by the smallest member of the Wehrmacht (the KM) and distinguished "after the fact" with a pantograph. Under this theory with all units would be coming directly from Mauser. I can see the Army [with promise of the acquisition of many units (HScs) and perhaps the police given the volume they acquired initially] requiring a formal process for acceptance and "proofing" to distinguish the their units somewhere prior to the end of the actual production process. This would prevent the KM from snatching up 1st-choice pistols already set aside by the Army. All said and done, we may never know for certain -

.
Alan, isn't it safe to conclude that anything with a III/8 proof came directly from Mauser as the proof was put on prior to bluing? This seems to suggest that an inspector was at Mauser accepting pistols within the assembly process the same as the Army.
Thanks for the input and response.
Rob