They are 1-3 so far and in danger of not advancing. They need to beat China (1-3) in their last game and hope that New Zealand (1-3) loses to Spain (4-0). I'd say the odds are in their favor, but it's hardly a lock.
Serbia & Montenegro really probably deserve to be in the medal round if they beat China (they will easily) regardless of whether New Zealand wins. They lost to Argentina on that last-second miracle shot by Manu Ginobilli. They lost to New Zealand on a very controversial play. Then their third loss came at the hands of Spain, who is probably the best team in the tournament so far.