So I've done the scans and looked at them. Pretty interesting.
If they were different it wouldn't necessarily mean the stone/plate was different. A card from one part of the plate is usually different from one from another part if there's two of them on the plate. And I think there's enough T206s out there with the same name at the top from a miscut or even with the name at both top and bottom that we know they were often or usually doubled up on the sheet.
Here's the detail of the American Beauty card.
And here's the detail of the same area of the Soverign card
Both were scanned at 800dpi
The slight diffrences in the thickness of the black lines are from the black ink being a bit more liquid while the soverign card was being printed. The registration is also different. Blue a bit high on the AB and a grayish color slightly to the left on the Sov. Aside from that the dot pattern and even the lettering are close enough to call them identical. I'm nearly certain that not only were they printed by the same plate, but are from the same position on the plate.
I'd be interested to hear theories against this. I have a couple, but consider them to be unlikely.
Next up, looking at the maybe two other t206s I have two of, and looking at a modern card or two that I know for sure are double prints so I can show examples of differences.
I'm thinking on the extra sliver trimmed off idea, currently thinking not, but it bears some thought.
Steve B