You can see it in that 5th pic. That enire big panel at the bottom of the window is a perforated metal grate. Like I said, you'd never notice it's not a solid panel unless you're looking up through the trunk.
If you get a chance to measure ambient noise between driver and passenger at 70mph with your favorite smart phone sound meter, that would be great!
Then see how it changes based on what you put in the trunk:
1) A wadded up canvas tarp
2) Door off the handlebar well
3) Grill removed and 'fun noodle ' foam lining the edge with dogs in the trunk.