I took a few pictures of the proof marks...most all of which are WA 359 with the stylized Eagle above.
There's an interesting "Circle B" with a "57", then what looks like an incompletely stamped "WA 359" on the side of the barrel near the front, right:
This is typical of the WA 359 marks, on the slide, right hand side:
And the mysterious "acht comma drei und achtsich"