That seller advertises all of his listings as AT. He tones them himself. No question about it, and he admits it. Every one of his listings have the same information: "This auction is for a beautiful 1943 S Mercury Dime (Winged Liberty), Rainbow Toned (AT)*, 90% Silver."
The first coin looks AT but it's pretty. I'm thinking the coin Doug posted is NT. Looks like it came from a mint set.
Yes the coin I posted is NT, and yes Larry it did come from an original mint set - you know me too well Larry - that's cheatin But I did not post it to go on about what the TPGs think or anything like it. I posted it because of its similarity, the obv anyway, to the OP's coin. And no, my pictures are never juiced or altered in any way except for sizing. I would say the pic of the OP's coin was juiced though, and that if seen in hand would look even more like mine. The point is, man copies, or tries to, what mother nature has already done. So don't let the look necessarily make you think that every coin you see that looks like that is AT, because they aren't.
Another difference between your coin and the OP's is that yours exhibits "flaking" of the toning, while the toning on the OP's coin simply rolls over all the devices, crevices, etc. I'm sure WL can expand on elevation chromatics, but NT usually is impacted by surface factors such as devices, height, etc., whereas AT simply ignores any of these aspects. Of course, there's no single definitive NT/AT marker, but, like motifs in literature, an accumulation of various signs usually reveal its authenticity