No, you don't take out any rivets. Go inside, remove the screen, roll what's left out a little bit and across the top you should see 6 phillips head screws. These screws hold on a strip of metal that squeezes the glass to the outer piece (plus some glass bedding and caulking and stuff. InlandRV has the replacement, however if you're going to be mowing a lot I would put lexan back since that is one of the flat glasses.
There's more info on here somewhere - you got to search it out.