If the readme wants credit and you supply said credit I see no issue. If the mod maker is still actively involved in the scene then I doubt he had a huge change of heart and you're golden. If the mod maker is gone from modding oblivion or has moved on in life I highly doubt he cares one way or another at this point. But that could be just me projecting seeing as when I walk away from things I tend to have a "fire and forget" approach to it. Put it out there, let people do whatever they want with it, and walk away with no cares in the world.