You remove it to pour the oil in. Only takes a gentle squeeze and a little wiggle to remove from the cover. Not yanked. You’ll see when you get to installing them. Hit the hole with some sand paper so there’s no sharp edges (if needed)
I've already stuck the grommets in the covers and had thought that might be the case.
The ones that they came with were rock hard and not open on the bottom at all but I guess a knife fixes that. I like to never got those out. Couldn't just go to town on them with a big screwdriver like I wanted because I figured I'd end up bending or scratching the covers.