I bought a laydown plate mount. When I went to install it, I found a fourth hole in the fender that the new plate mount does not cover! I bought a Kuryakyn mount, but the Harley ones look like they also would not cover the fourth hole. Has anyone else had to deal with this? What do you do with the fourth hole?
Find a plug. The plastic plugs you can buy at any auto parts store will do. You could also get a chrome plated skull type bolt to put in it. Lots of alternatives to look into. Get creative.