I put the CVO seat setup on my 14 Road King and the riders seat attaches to the 2 mounting studs that are sticking up out of the fender. In order to attach the passenger pillon you need the seat nuts with the grooves in them. the pillon will slide into those grooves and then secured with the stock seat screw.
I had to get the nuts with the grooves separate from the dealer.
I ride solo all the time.The only hardware I needed was 2 acorn nuts and a Mustang Mini Fender bib which mounts between the white washers and the black plastic tab on the seat.