Yes, it appears that a t this point, Kourtney Kardashian and Justin Bieber are good friends. They're hanging out together and having fun. Over time, their friendship may involve into something else. But everybody needs a friend, and it's nice to have friends of another gender. I'm sure these two are having a casual, nice friendship.
I can't see these two together under any circumstances. Kourtney is by far the Kardashian with the least to offer. She always looks like the lights are on but nobody is home. Justin Bieber seems to have some common sense and I credit him with much better taste in women.
I'm assuming they're friendly and share a mutual like of being in paparazzi photos. Even if they are more than friends, who really cares? It's become public 'business' only because they're in the public eye, but at the end of the day, it only matters to beliebers or any fans with a crush on Kourtney.
No, there is a good chance that they are smashing each other. When two celebrities such as these hang out, they are probably messing around. There is no reason to believe that they are just friends and no reason for them to be just friends. I believe that they are dating.