I don't know where you are from but I still know of black and white men and women who sound very close to the dialects written so many years ago. You just have to go deep into the middle of nowhere to find them these days.

If they are written in the music, I honor the music by singing them that way. I do, however, warn my audience if I feel that they might be offended. I give my audience credit for being smart enough to know if they wish to be offended ot not. Most times (99.09%) they are not offended and understand my reason for the dialect. The small number that are offended, at least understand my reasons. I don't care if they disagree with me so long as they can see my basic point of view.