The 13 racing model has a different frame to the 12.
The 13R should have the peg mounts that are bolted to the frame as opposed to being part of the frame. Where the linkage meets the frame it'll be a one piece U shaped connecting rods (similar to Yamaha/Honda). The 12 Racing (and 13 E-start model here in Aus) has single linkage connecting rods, and obviously the frame is different to accommodate this.
That's probably the easiest way to tell when having a quick look over one.
14 saw revisions to the frame (geometry and weight savings), and has remained the same (14,15 and 17 models).