The
Flying Eagle cent you purchased has original surfaces, but it also has some corrosion. The copper-nickel coins can get green spots, but more often their corrosion areas or spots are black or very dark brown. That coin has some toning that has worked its way into the surfaces.
I regret for your sake that I don't have any photos of circulated
Flying Eagle cents. The two coins in my collection are Mint State.
You should get a user number from Heritage Auctions. It's free and it gives you access to photos of the many coins they have sold over the years. You can also access "Coin Facts" which PCGS also offers for free on-line. Both of those sources will provide you with photos of no problem coins.