I can't be sure. I think it is on the coin, but it could be on the capsule. The only way I could be sure would be to pop it out of the capsule. As I'm not the most adroit person, I'm afraid that I might screw that up and damage the coin.
Under the microscope, I can see something in that area. That makes me think it is more likely to be on the coin.
It is unfortunate that the Mint is so sloppy with expensive proofs. Scratches shouldn't happen. The other two coins don't appear to have scratches, but there are small scraps of black fibers sealed in with the coins. That really shouldn't happen either. Although I think we already pay enough of a premium to expect better, I'd rather pay more if that's what it would take for better quality control.
Note: All my coins are in a safe deposit box. I keep nothing in my home.
Contests and giveaways: http://coins.aplawrence.com/2014/05/contests-and-giveaways.html