Yes Kershaw worked with Sandvik to create the steel that they use now, 14c28n. It uses nitrogen in place of some of the carbon which creates much better corrosion resistance. They also heat treat it a bit harder now.
That sucks you scratched your knife up real bad with the 320, I've done that before when I first got into knives on a US uncle henry I inherited from my grandpa, I still get mad at myself when I think of that! Now that you started with 320 you'll probably have to sand the whole blade with your 320 grit. After the whole blade has an even finish you'll move up a couple hundred grit and then another couple hundred and then its up to you if you want to go any finer than that. It might look like this, 320, 500, 800... The exact grit is up to you, you just want to make sure that you get it nice and even in each grit before moving up to the next. I've done this before and it took a while but it was on s30v, with the sandvik steel you have it shouldn't take too long. Plus it will give the knife a custom look.
Edit: If it really bothers you, I wouldn't mind rebead blasting it for you. It wouldn't really solve your original problem but I wouldn't helpin a brother out and doing a quick blast for you. I recently got a media blaster setup and have been having some fun with some of my pocket clips/handles... Email/PM me if your interested.
