You didn't show a lot of pictures but one question I had would be .. is there a rib engraving? Someone knowledgeable may be able to tell from a rib engraving who the original marketer may have been. Most US dealers had some sort of catchy name applied to the gun for sales reasons. The thing I noticed was that the gun had post 1893 Belgian proofs and post 1887 British proofs. My guess is that it was made post 1893 in Belgium and then was reproofed (which was required in England for an import) somewhat later in England. I don't think this would occur with an American hardware gun, so I suspect it was made for the British market originally. It was likely marketed as a British Parker, later being sent to the US,
See this thread for some additional reading:
https://parkerguns.org/forums/showthread.php?t=29327