First I want to say it's hard to believe Jantz has been gone for over 4 years it doesn't seem like it was that long ago we were talking about meeting up at the Cleveland National.
In the 7 years since I posted this thread and well over 100 print flaws later all of the new print flaws reinforce what I found back when I originally posted this thread that the print flaws track with the backs that were printed at the same time or very close together.
If you look at the McBride you can see the A-B-C-D pattern in the print flaws (McBride is confirmed with Drum but I haven't found a scan)
Also since I posted this Bryan has confirmed a MURR'y on a Sovereign 460.
I just finished the numbers on two new Polar Bear flaws and it still shows convincing evidence (along with other evidence) that they weren't printed with the other T206 backs.
So far without exception if a print flaw is a found on an off back that flaw is also found on Piedmont or Sweet Caporal backs and it's usually found on both but that's not the case with the Polar Bears until you get all the way to print group 4 460 only subjects like this Schlei
Schlei (Batting) Red Mark Group.jpg
Here's a recent Moriarty flaw I found this flaw is found on Sovereign 350 and both PD350 and SC350
0 Moriarty stats.jpg
here's the stats on the two new Polar Bear flaws I found
0 Stats.jpg
0 Nattress stats.jpg
With the Polar Bears you have Demmitt and O'hara St Louis, the fact that they're not in the Ledger pages while all the other backs are, add the print flaws to that and to me it all points to them being printed separate from the other T206's either in another ALC facility or after the other T206's.