Installed mine last week, after wondering if it was even supposed to fit.
Small serrated spring washers intended under each screw, now coated with antiseize.
There are also 4 rubber cups/grommets which can be used to cover the holes if the rack is removed.
The long screws are for the side, with their respective spacers between the rack and the subframe on the sides. [You must be registered and logged in to see this image.]
The smaller screws are for the top and fit well inside the protruding flange of the rack. [You must be registered and logged in to see this image.]
At the end of it all, with the seat on, my word the seat looks the business and rack integrates well.[You must be registered and logged in to see this image.]