Nice find, and great picts as others have said !
To the point:
This would seem to confirm this s.n. as also part of the original 1000 gun delivery?
I don't think so, at least not definitively; the upper could have been changed at any time and by anyone prior to the refinish. That the font is the same would be expected within that serial range.
JMHO.
However, the mismatch does not detract at all from the fact you have a test luger lower.
