So what is the story on SLS? I assumed that it is not in 5.2 since the things you make with it were removed. but that could easily be incorrect.

But the 5.3 patch notes talk about it. "Engineering: Stabilized Lightning Source tooltip now reflects the 1 day cooldown. "

So it could be in 5.2, or SLS added in 5.3 or SLS and the removed from 5.2 PTR items added?