Hmm, I've been looking into the Rise of Nations story more.
Given the Kingdoms of Amalur sale and Tony from Amazon (I heard this anecdotally from someone else while I was Googling) saying he had talked to Rhode Island about Steam keys for KoA and the RoN gold master, it would sound like its the original version and Rhode Island trying to make money on it. But, with the achievements in the Steam database and the Age of Empires remake, it would look like a remake. Does Rhode Island own Rise of Nations or does Microsoft Game Studios? If the later, I would guess remake.
I've played this game for hundreds of hours if I seem a little obsessed.