Does it matter? Ultimately, only the question's state when you review it should be the only thing that counts.
- In the case of duplicates, there are three tabs over the question: Question (revised), Duplicate and Revision, which provide all the information needed.
- In other cases, if it is not unclear, too broad, or otherwise off-topic as it stands, vote to reopen.
- If there is relevant content in the comment thread (accessible from the review view, IIRC) then either edit in that content yourself, or drop a comment asking for such an edit.
Honestly, I don't see the point of reopening if I would nominate for closure for any reason (except perhaps being a dupe). If it was closed as unclear, but could now be closed as off-topic, I'd vote to leave closed. So, to reiterate: consider only the question's current state.