I never knew that "Good Times" was going to be called "Great Day", until I saw an old TV taping ticket stating "the producers of ALL IN THE FAMILY and MAUDE present GREAT DAY starring Esther Rolle, John Amos, Janet DuBois, Jimmie Walker" and the ticket was dated December 17, 1973.
If you don't believe me, here is the ticket:

http://www.sitcomsonline.com/photopost/showphoto.php/photo/105921/cat/715

Now the question is, was this pilot ever aired? Or was that the date that the "Getting Up the Rent" episode was done? I checked on the script for the "getting Up the Rent" episode and the tape date was January 7, 1974. So, which is right?

Interesting, I never heard about that. I must investigate further....

Maybe it was for the pilot which is sounds like.