Are you saying "oversold" only because the seat map is full?

I really doubt this flight is oversold with this availability:

AA 503 FLL 15:56 DFW 18:13 M80 F7 A5 P1 Y7 B7 H5 M4 L3 W2 V1 G0 K0 S0 N0 Q0 O0

On an MD-80 there are about 17 seats that are reserved for airport assignment only, so I am sure that if you don't get your upgrade, you will at least get one of those.