Featured Lil gold bar pin maker?

Signed what looks like O. St. And .585. I believe .585 is more likely to be European than American. Anyone recognize the mark?

 

Inverted gives you a slightly different perspective, but I still don't know what to make of it!

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Appreciated! Gives me more confidence that it’s an O with your inversion. You can see more of the right side of the O on your image vs. mine. Thanks

Edit: well maybe not more but somehow it’s more clear to me than it was either way.

 

European rather than British, too. Can you show the whole back please? I do have a sort of theory.

 

Indeed. Just realized I don’t have a complete photo of back yet. Here’s what I have for now, most of it.