It is normal for the black finish to come off in the small area where the hammer hits the striker (firing pin).
The pistol is test fired at the factory before it is delivered so I'm sure this is why the black finish is already bared.
If you have other black parts on the P226 that are black i.e the outside of the barrel, they too wil become bared as the pistol is fired. Perfectly normal. Just normal wear.