Jim, likely new verses were created/adapted and woven into the usual choral version. The whole point of spirituals was their ready morphing as needed. (I copyright my versions too just to keep the record clearer, moving forward in time, than it could ever have been looking backward.) Morgyn is just sharing her/his own point in time.

The song in all its variation is so well known BTW that it's commonly called BISSL.

~Susan