Yes, a good bit of research that. It does, however, beg the question of how much notice did the collecting community take of these articles and letters? Serious collectors in the 1960s were only buying top grades pre-1937 and the recessed ear was not published in official catalogues and guides, and very much less noticeable in EF and above.
I remember that the 1946 ONE' flaw was described in a beginners' page in Coin Monthly early '68, soon after I started my own interest in coins - it didn't lead to any widespread dissemination of the variety for years though. I think people read those things in magazines and thought "Ooh that's interesting, I must look out for them", but due to a lack of follow-up (which of course would occur rapidly now in the internet age) soon forgot or lost interest.