This fuel pump, off a 1959 A4, was really dirty inside and out. There was a material resembling very fine sawdust clogging the filter. While cleaning the mess off the outside with a wire brush, this hole (the scredriver is pointing to it) appeared.

My question: Is this supposed to be there? If not, can I fill it with something so I don't have to buy a new one? If not, anyone got one of these lying around that they'd like to part with for a reasonable fee?