Sean/Ted, I don't think that the Doyle with this mark would have been
corrected or "cleaned off".
We have learned over the years that most if not all T206 sheets were
printed with multiples of the same subject in vertical columns meaning
only a certain percent of the Doyles would have the extra part of the letter
on it. For example I will use one of the plate scratch sheets and substitute
Larry Doyle as an example.
The plate scratches have established that this sheet is at least 15 wide
by 11 high (I think it was actually bigger but I need more evidence to
support that) so if the Joe Doyle that had the mark was on a similar
sheet lets say it was the fourth vertical subject from the bottom of the sheet
only one out of every 11 Doyles that were printed from that sheet would have that mark
without factoring in any other things that could affect the %'s.
C-D Sheet A - Copy.jpg
When print flaw is found on a non Piedmont back it's found in much
higher %'s. I will post a detailed explanation one reason I think this
might be when I have more time.