I believe that is a repair to a stripped or drilled out carrier spring hole. That screw can be accessed through the loading gate hole after removing the gate. It can be difficult for an owner to remove and might have been drilled out. The screw in the photo appears larger than the original screw.
It's not uncommon for that part to wear out. A worn part will cause the carrier to stay down when working the lever.
If it's drilled out, it will need to be welded up, redrilled, and threaded.
