From Quil Ceda Creek in Marysville, WA --- the originally listed 3rd issue black Winners Club had a normal text address line at the bottom on the reverse. On the new found variation of that card the same line is now bold and appears to be a slightly shorter font than what's on the original card. The difference is pretty slight but very obvious when you have both cards together.

Here's a scan of the common front and the normal vs bold backs.