I did some research and found a soft covered book in my collection produced in 1997 by the Air Force Flight Test Center History Office, author James O. Young, entitled "Meeting the Challenge of Supersonic Flight".
In it the author states that "GG" nose art was painted on the X-1 by Jack Russell shortly before Yeager's eighth powered flight in the X-1 on Oct. 10, 1947.
Amazing the stuff you can find in your own house! I forgot I had this book!
Still interested in the red bar on the star date.
Jerry