Howdy red9,
Frankfurt was in the American sector after WW II, so I believe it makes sense that your Victory would be a 4" .38 Special without British marks.
The "/M" after the city name means "am Main" or "on the Main River."
I'm sure the "BP" stamp equates to your memory of "BAHNPOLIZEI."
I'd guess S&W shipped yours early in 1944.
Absalom will be along to fix anything I've broken here.
