06-13 HARLEY FLHX2: Mustang Recessed Rear Seat (Vintage) The Mustang rear seat has a slightly recessed front end to allow clearance when being installed behind a Mustang solo with the built-in driver backrest.Made in U.S.A.Note: Will NOT fit with stock solo seat.Detailed Specifications: Rear width: 13.5". Notes: Will NOT fit with handrail. Mustang Solo Mounting Nuts are needed in order to install the passenger seats on all 1999 - 2013 FL Touring models. The hardware is needed to convert one-piece seats to two-piece seats. Cannot be used with any of the Harley-Davidson&#174; TourPaks.