Yeah, I thought I took a photo before I took it off, but had already flipped it over after removing it and didn't want to lift it again. It was stupid of me not to.
That must be it! I have no clue why it was installed when I didn't have a lawn/leaf vac or collector of any sort. I ended up taking it off and ran it fine without it. Thanks so much! I'm still learning so much about this stuff.