Looks like it's been stored in a foam lined gun case. Not saying that's what happened.
Try a some FINE steel wool with a good gun lube and GENTLY rub it and see what happens. If it's superficial it might come off. Be liberal with the lube.
this:I don't understand why this would happen if it was stored in the factory case!
Looks like it's been stored in a foam lined gun case.