The part number would indicate that it is a Honda factory accessory. It doesn't appear to be available through U.S. Honda dealers. Here's another overseas source for it, BikerzBits: HONDA CBR300R/F REAR RACK Not a great photo, but you get an idea of what it looks like installed...This?
HONDA CBR300R/F REAR RACK
Isn't this a factory accessory?
Amazon.co.jp? H2C(???????) ????? ???? ???? CBR300R(14-) APK3381200TA: ????????
Yeah, I have the same rack. It fits the bike (the mounting) perfectly, but the pillion seat has a lot of play in it - I can move the rear of the seat with my fingers up and down quite a lot. Doesn't bother me much, as I have the soft panniers that help keep the pillion seat down.I purchased the rack from bikerzbits. It's not a good fit. If you look at the photos you will see there are not pads for rear seat to sit on. I had to weld on a couple pieces of melt to support the rear sear. I'll attach photos later.