Chosen Solution

ONE OF MY BOSE MODEL 21 SPEAKER HAD A DAMAGED FRONT COVER EXPOSING THE SPEAKER DRIVERS AND ITS CARDBOARD FINISH. SEE ATTACHED PHOTOS.

@dens66 okay that part does not come as a repair part. Looks like the way to fix it would be to buy a couple of blown speakers from online auctions (like ebay etc.) and harvest the speaker enclosure from that one. The other thing you could do is to find a local carpenter who can build you a replacement from either MDF or other materials.

When I was a kid we just recovered speakers with new material.