Holes chain case Model 50

Good morning,

inside the chain case there are two holes to remove the magnet screws. One of the previous owners closed it with copper sheeting and screws. I think to get this a little more oil tight. Removing it was a disaster. Are these holes sealed with rubber plugs or something else from the factory, or do they just stay open?... Or: Are they still original? Because i do not see holes on the illustration in the parts manual.

Greetings Heiko