I answered old questions before. And I got upvote from Musing.
Yes, Musing curates new answers to old questions. As long as you provide value to your answer, there is a high chance your answer will be curated. When people answer any question, they give answer based on their experience and expertise.
The question is the same, sometimes answer can be different. Different people explain it from different angles unless that's a yes no question or mathematics question.
When curators team submits any answer for upvote, they see the quality of the answer. If your question satisfies the person who asked the question, that's all that matters.
So old questions or new questions do not matter. When I find a question that I know very well, I answer that.
Hope this answers your question. Thank you.