I suppose its a matter of how you look at it. If, for you, the Death card is one of endings, of finality, then it may be setting. If it is one of new beginnings, a new age, a new dawn, then it may be rising.
If however, it is a card of transitions, of change, of progress and that shows a kind of process, then you may see it as neither, only as a state of in between; neither high in the sky nor nightime. A dusk, if you will.
But as to you question, if anybody is 100% sure, I doubt there is anyone like that, and if there is, there will always be the one who will disagree. But if you are interested in the original intent, I suppose the answer could be found in the PKT, if you like being exasperated by half truths and riddles.