Vintage Silver Highlights - City of Roses, Portland Oregon Silver Trade Unit

Nice privately minted Portland Oregon round. Known as the city of Roses, this has a nice rose on the obverse and the classics Silver trade unit scale on the reverse. No matter how many other silver trade units I looked at I could not find an exact match for the scale to help me identify the mint it came from. Hopefully someday the research gets better and I am able to track down who minted some of these rounds that have no marks or identifitcation.