It is definitely possible that a coin could remain completely original and attain rim toning. I have numerous examples of coins like that in my collection. What you'll notice, however, is that these coins don't have that "splotchy" appearance we've been discussing. They have a much smoother appearance to the toning. Take a look:
Competing thread: https://forums.collectors.com/discussion/1036683/seated-liberty-quarter-nt-or-at Interesting how the opinions there are completely the opposite (although they are basing it off the ebay photos).
Nice buy. I think some are overlooking the fact that many 19th century specimens were cleaned and lacquered 150 years ago. Back then they used a natural, insect based nitrocellulose that wore off, but residue usually can be seen along the rim and smaller places. This coin has a surface chip between the 10th and 11th stars (I always count clockwise from the left) which might be indicative of lacquer. Having it conserved would remedy that, but lose the color toning. If, it were mine, I would leave it just as it is; an honest example of it's time and a beautiful coin.
If I were guessing solely based on those terrible Ebay photos, honestly I would probably have also guessed AT.
Those photos certainly give a different impression. @C-B-D took a shot and looks to have found one of those bad photo winners from eBay.
MA. There are plenty of similar coins that are NT from album toning. With that said, I am bothered by that shade of purple/blue on the reverse with that progression especially to the right of the eagle.
I had this one in a flip ready to go to PCGS but someone gave me an offer I couldn't refuse. I'm sure it'll pop up for sale again in a holder.