That is the back of the ejector, near where its pin is located. Behind this is the spring that powers it. If you look into the receiver and just behind the ejector where it is damaged, you should see the spring partially visible beneath and behind it.
I you pull the barreled action out of the stock you can see and appreciate how the trigger, ejector and bolt stop parts parts interact and how simple and robust they are.
As
@diggler1833 stated in the other thread, taking the SPR apart is pretty easy and straight forward. Getting the ejector out requires removing the trigger and bolt stop, but that's one pin. You don't even need to take the nuts and adjustment screw loose from the trigger if you don't want to (which I don't recommend for this as it would require re-adjusting the trigger). The ejector is held by one role pin. All you need is the 5/32 hex to remover the action screws and the two punches to remove the trigger pin and ejector pin. Taking pictures along the way is a great idea and should ensure you get it back together, although it is really simple, which is one of its strengths (in my opinion).
I would pull the ejector and clean the top part up with a file or simply replace it.
Good luck.
AG