As far as the circle goes. I have seen toned coins which have similar circle or circles but sometimes this is caused by some sort of carbon mark that was there and the toning just moved differently around that particular area. Even breathing on a coin can develop such abnormalities so when a coin tones, makes those areas be more visible and different.
The toning looks at least plausibly natural IMO, but I think someone had a few extra grade points to give out that day.
Yes it does, and those look completely normal. But can you not see the difference between this coin and the other ? On this coin the circular spots are toned, on the other it is a circular spot that lacks toning - big difference. And it's not that there is a sharp difference in the gradient of color - but that on the other coin that difference in gradient occurs in a straight line. That just doesn't happen.
That 1880 looks natural and attractive to me, as does the coin which started this thread. I have no concern about the originality of either one.