Although some songs may not be an accurate reflection of history, I really don't think it's worthwhile going through them correcting names.

I know for instance that when I sing The Royal Duke of Grantham that it was about some other duke... possibly, but I sing it that way because that's the way I learned it, and that's the way it was collected by whoever I learned it from. Although the history is interesting, it's the song that's important to me.

If there are different versions of songs, choose the one that suits you best, or even merge versions to arrive at one you are comfortable with, but I don't see the point in going through the DT making sure all the names are right, as long as the version noted represents the way the song is actually sung somewhere by someone then it's valid.