Outstanding research and your example is in good shape. I have a similar bike that came from Gregg's Greenlake Cycles in Seattle about 50 years ago. The Falck double-butted tubing us reputed to have outstanding ride quality: the prior owner of the frame I have used it as a commuter bike and put about six or seven thousand miles on it annually and did so for decades - for what he used it for he found no better ride at any price and he collected pro bikes like the rest of us have matching pairs of socks. I've found quite a bit of history for Falck and interestingly they made the blanks or starting point for Columbus tubing in that era. Full credit to Robvolz for his photos, I've speculated that the frames came with lots of plating but mine is black powdercoated and I plan to remove all of the well polished areas when I figure out how to remove it.