Being an old guy with time on my hands this winter I decided to remove the belt guard and check out conditions behind there. Only two 6MM Torx screws for removal, right? I was surprised to discover that there were nuts on the other end of those screws that were very hard to access. Once removed I went searching for some sort of captive nut so no wrench would be needed for future removal. Here is what I found, available through NAPA auto parts, stock number BK6651303.
Of course there is a third screw to be removed to remove the guard but the fastener for that one is already secure, no problem.
I've done the same as you. Last fall, while prepping for winter storage, I discovered those pesky nuts you can't see. Can't see? BLIND nuts to the rescue. Nice to able to make any task a bit easier.