I can't say much about the 320, but I can say something about the 321. I do believe it is the non doubles combination whose all 6 boxed numbers have been absent for the longest. Notice:
123: last drawn 9/2/00 1142 draws ago
132: last drawn 1/5/01 1017 draws ago
213: last drawn 12/5/97 2144 draws ago
231: last drawn 11/20/98 1750 draws ago
312: last drawn 4/28/99 1635 draws ago
321: last drawn 9/10/90 4785 draws ago