Im sure its used just does not looked dished,cupped. Yes your 12k should be good. You can use a slurry with it. I also use Naguras on my 12k just like a Jnat. Works amazing. !2k creat a very sharp crisp edge. If you like your edges Crisp and sharp. If its a little too much you can you Crox to soften it up a bit. I still use crox even of my 16k.