Id say its AT because of the burned on the side with the begining of Liberty which imo its been in the oven PS: the black spots on the coin look like ash
For me it's difficult to really tell. All depends on what is really At or NT. That one does appear to have been heated or left in a place of intense heat. However, if done over a period of time and by accident, I still wonder if that would be considered AT?
Looks natural. Similar toning can be found on the 90% Kennedys that were put in the black cardboard snap lock plastic cases promoting the coin.