Hello Bob,
This is only a WAG on my part...but my guess would be that the Bern arsenal or a Swiss-authorized gunsmith/shop would/should probably try to retain the "polished" area underneath the thumb safety lever, especially for a military, Ordnance pistol. This to keep the "as specified" feature of the "visual" aspect of the polished area of the gun when it was original. If both exposed areas around the safety lever were both blued, it might confuse the shooter-in-training and lead to unsafe conditions. I cannot imagine the Swiss allowing this situation to occur in the Military services.
I have seen 4-5 Swiss lugers (M1900, M1906, and M1906/24) in person over the past 3 years that seemed to be Bern arsenal refinish works and the polished areas were white and still retaining their sharp contour and shape, but some of the depth of the relief cut seemed to be lost. If these were not Bern reworks, the modern-day refinisher did so with some high level of skill...
Just my 2 cents...
Regards,
Pete... <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />