According to 777Brit on this forum:
http://www.flyertalk.com/forum/Forum71/HTML/017604.html that business upgrade seats are designated as inventory "u" for this flight. I see that there wasn't ever a "u" category for this flight. Am I misreading this or not? Any info will help.

Swimmin M

Chicago (ORD)
December 12
5:30 pm Arrives
Paris (CDG)
December 13 (Next day)
8:35 am Notes
Cabin class: J7 D0 I0 Y7 B7 H7 M7 V6 K5 G4 W2 N0 L0 S0