This helpful information was posted to my thread on the American Vintage Airgun Forum by DWTrull in response to my comment that this pistol was found in Nova Scotia, Canada:

"That makes sense since James Bernard Peters was originally a Canadian born in Nova Scotia Canada.
It probably ended up with the family back in Canada when he passed.
Undoubtedly the gun was never mass produced. I suspect your gun may be the "Prototype" of the pistol.
Peters may have hand produced a handful of pistols since he was an accomplished machinist,
but its also just as likely that he only produced the one prototype which went back to Nova Scotia when he died.
I think your pistol is likely the prototype due to where it was found and likely the only example in the world.
It was a one in a million chance that you found that pistol! And I know you love all things Canadian!!
The Peters was made by a Canadian living in the US, and returned to Canada."