It is very hard to even see in hand, but there are just some darker areas. The picture greatly exaggerates them.
Not very often you too high of a grade for the coin, but you did here or else PCGS under graded it. Great strike, great luster and I can only find 2 tiny nicks (in the wheat to the left of U and below the ONE). I cannot find those "spots" without a loupe, but I cannot find another reason for this not to be a 67 unless they had just met their quota or something like that. Anyway, PCGS only called this a 66. It is about as nice a 66 as I have seen.
I guessed 66. What made me grade it that was an apparent lack of luster (doesn't appear to have that LDS "glow" that PCGS likes in 67s). Certainly seems clean enough. I also wonder what's on the rim and hidden by the slab. I've cracked out a few head-scratchers over the years only to find a hit or three on the rim that held a coin back. With large cents you can often see them, with Lincolns and their thin rims you often can't. Wonder if that might be the case here.
