About all the distributors have yet to receive the Frame Sliders and other goodies as the manufacturers just now have some bike to work with and build off of. We have our ear to the the ground for newly released items each day.
Browsing at indonesian online shop youll find ninja 250fi frame sliders which exactly fit to the ninja 300 . Coz in indonesia ninja 300 is cut down engine size to 250 but overall body size is the same check it out empiremoto @ indonesian online shop
You can also get some of the larger spools which they call spools/sliders too although they aren't going to give the protection of real sliders and aren't in the right location. You need spools anyway probably if you are doing your own maintenance. MJ Moto sells them cheap, along with cheap stands. The front stand only comes with a single pin though. If you enter "webbuy" in the coupon area, you get a discount. Stands and spools including shipping was $126 a few months ago when I bought them for my Ninja 650. The stands and spools worked fine.