Hi Peter,
I have seen 6 other M2's in person in my travels in the past few years, all of them being above the 1000 SN range and all of those showed no halos on the barrel, the receiver, or the back of frame. Those guns looked original finish and with the wear you normally see on the Portuguese guns.
That is not to say all 5000 guns of the M2 contract were finished in the same way...i.e. proofing before bluing or proofing after bluing.
There was also a similar Brazilian contract of 5000 guns around the 1907-08 timeframe. Those I have seen in person also did not display halo and I thought their finish was original as well. Brazilians are blank chambered and have a B/circle proof.
The reason I requested better, close-up photos was to be able to see more detail of your halos.
As you may or may not know, some of the more recent restoration artists are refining techiques to "re-create" a halo effect...some we have seen in the past here on the forums still display an "artificiality" to the halo effect they have attempted to create.
Good close up photos of the proof halos would allow us all to see those on your gun in better lighting and detail.
I have played around with a couple of your photos and cannot see the halo in enough detail...
Here is one of your photos, zoomed in...I keep thinking I see a Swiss cross proof on the back of your Luger...which is certainly not the case...just the limit of zooming in on the photos you have posted so far...
