Seems to me that a lot of these stories are just big fish stories. Someone supposed something a few decades ago and it became collecting lore. An AH catches wind of it, uses it in a catalog, and it becomes a 'fact' until it is debunked with further research. Separating the truth from the puffery and chaff is where good researching comes into play. Some examples:
--Changing the 1932 US Caramel set date to 1933 based on careful analysis of data on the card backs.
--1948, er, make that 1949 Leaf cards.
--Debunking the dates assigned to postwar Exhibit cards based on uncut sheet and advertising research.
--T202 Joe Jackson research thread here, proving Shoeless Joe has a T202.
--Finalizing the T220 and T220 silver border checklists. There's a heck of a thread here on the boxing page if you are interested.
--Refining the T218 master border checklist.
--Debunking the Recruit back T206 Wagner and the standing pose T206 Wagner stories. The former was a 'should be one' story and the latter was reported in the hobby press then corrected years later when everyone realized it was the other Wagner.
--Analyzing the 1933 Goudey Sport Kings premiums. This article has a particularly good example of how a supposition becomes a story then becomes fact then is debunked:
https://www.sportscollectorsdaily.co...ings-premiums/
I suspect that the legendary walk-in of all these cards that no one has seen since is another tall tale that got repeated until it became lore. That said, the opposite sequence is true of the card itself. The research published on this site proved that the portrait card with facsimile signature was indeed a 1947 issue.