Sorry I dropped out of the discussion for a couple of days - had a series of minor calamities - but it looks like things went along just fine without me. (Who knows, maybe it was better without me!

)
In the above posts, I noticed several folks agree with the idea that the crossed pennants are a British proof mark. Also, someone mentioned Ian Skennerton. That reminded me of something I posted quite a while ago. Here's an abbridged version:
If you can locate a copy of Ian Skennerton's
The British Service LEE, look at page 397, under the heading "
Proof Marks". You will see
plain crossed pennants, as well as crossed pennants with crowns, royal cyphers, etc. So Skennerton lists crossed pennants as a proof mark and if you look elsewhere in the book, you will see it was commonly applied to WWI British Lee Enfields.
It seems like a logical assumption that if the crossed pennants were used as proof marks on rifles, then they would have the same meaning on handguns, especially if the marking was done at the same facility, at the roughly the same time.
To echo Mr. Hondo44, I do not mean to argue, either. I appreciate the civility of the discussion and the value of each contribution.