Planes can always change last minute, so while there is a schedule that becomes apparent closer to the departure date, nothing is set in stone.

I would not count on getting the new cabin on that route. If you value flying the new cabin it is recommend to fly ORD-ARN-CPH instead as it is virtually guaranteed to be the new cabin (or even one of the new planes, like I had recently).

Flying A340's from CPH only gives you a very small chance to fly the new cabin until additional aircraft have been upgraded. While LN-RKF should be back any day now, it remains a gamble and SK's indication of seeing it first on NRT and SFO doesn't seem to hold up.