If you think this coin has NT (natural toning) you seriously need to study up on toning.
1925 Lexinton Concord Commem. Half Dollar Rainbow
Check out the seller's other toned coins:
When a seller has numerous toned coins for sale that all have similar looking toning that should be a clue that it is AT (artificial toning). Also, it is very, very unusual for a coin to have identical rainbow toning on both sides (like the Lexington Concord Half).