Yes, that sounds right. Though, I suspect there are contexts where one term would work and the other would not (in addition, of course, to those in which one specifically intended to allude to the judgement of Paris).
For instance, I've heard or read "sowing the apple of discord" (I always wanted a reference to the seeds, somehow, but it sounds better than "sowing a bone"). I think a bone of contention isn't a bone of contention until its been contended over for quite a while.
You could toss either the apple of discord or a bone of contention into a situation, but you wouldn't always be doing the same thing, would you?
Maybe you could marinate or stew up or preseason a bone of contention ; )