R/S backrests have a bracket that goes between the driver and rear pillion seats. 1300C's came with a 1 piece gunfighter style seat. The mounting points used for the R/S are not there on the C. Also, beware of the ones on E-Bay that say "will fit 1800/1300C". The 1800 also has a 2 piece seat. I think they are "assuming" it will work on the 1300 also. The only ones I know for sure to work are the Grasshopper, the Protac, and the Kury switchable backrest. All of those mount to the shock bolts. I have thought about getting one for an 'R' and trying to mod it onto my 2 piece Mustang seat... bolt it to the seat pan or something.