Ditto. A jigsaw or dremel tool would be the best to use to cut it out (I have both, but used a jigsaw). Buy the mesh at Home Depot. It'* in the rain gutter department. Normally used to keep leaves out of the gutters.
Mark the cover with a pencil, and cut it out. Clean it up with a file and/or sandpaper. Paint however you like, then sand the paint off the text on the cover and underneath where you intend to glue the mesh. Use a paint designed for VINYL (flexes when it needs to). I used a metallic to make it look like cast iron.
Cut the mesh and glue it in on the back side. This isn't purely cosmetic, it makes a 10° difference in nosedrive temps on the Series 1 L67. And for the record, I've done 1 L67 cover (mine) and 2 L27 covers. AND JEFFREY COPIED ME! (which, of course, is the best flattery in the world).