Age spots. Not really sure. They barely show up in hand. My alleged photo skills make any flaw in a coin show up 10 times worse.
I think I see where it was tooled. Some of the details on the obverse look sharp, while others look worn and flat. For example, the lines above the shield in the dress look tooled. I have only 3 Seated Half dollars - an 1854, 1861, and an 1877. Pictures coming up in a moment.