Bronica EC mirror bumper

I took the parts of the bumper that fell out of my camera and glued them together to get an idea of the size of the mirror bumper. It's 6mm in diameter. Koh's camera is a store in NY that is known for repairing these in the past, and the guy I talked to on the phone said this part isn't needed. I'd like to be safe and fix it though...

Done