Either one is possible -- an easy way to check would be to call AADV (possibly a few times) with the following 2 flights and verify what they see on their end:
[KVS Availability Tool 6.7.0/Diamond - Sabre: Availability/FS/US]
Code:
JFK New York John F Kennedy Intl NY US [KJFK]
MAD Madrid Barajas ES [LEMD]
SUN 17 Jun 2012
Carrier Flight From Depart To Arrive A/C St Availability
--------- ------ ---- -------- ---- -------- --- -- --------------------------------------------------------
IB 6250 JFK 18:00 MAD 07:15 346 J9 C9 D9 R9 I9 U3 Y9 B9 T9 H9 K9 M9 L9 V9 S9 N9 Q9 O9 P9
IB 6252 JFK 21:00 MAD 10:10 340 J9 C9 D9 R9 I2 U0 Y9 B9 T9 H9 K9 M9 L9 V9 S9 N9 Q9 O9 P6
Vs.
[KVS Availability Tool 6.7.0/Diamond - Amadeus: Awards/OneWorld/AU-QFA-SP1]
Code:
JFK New York John F Kennedy Intl NY US [KJFK]
MAD Madrid Barajas ES [LEMD]
SUN 17 Jun 2012 | 1 Seat
Carrier Flight From Depart To Arrive St Availability
--------- ------ ---- -------- ---- -------- --- -- -------------
IB 6250 JFK 18:00 MAD 07:15 +1 0 FS- CS- YS+
IB 6252 JFK 21:00 MAD 10:10 +1 0 FS- CS+ YS-
Good catch. Called AA and it seems that the U inventory is accurate in this case, not the award results (confirmed that there were 3 seats available up front on 6250 but nothing on 6252).