Ok, didnt see the post there. Now realizing the situation, these fish might be older than a yr. If the owner didnt take care of the tank, who knows if they actually fed the fish... and if they weren't fed, then they could be stunted in growth....
Wiggle is right that in most cases, the two will prob be very aggressive with eachother, but if you see them more hanging around with eachother, then it might not be good to remove one at this point. It may just stress them more... Just keep a good watch on them and if you see them going after eachother, then you will have to rehome one of them.
Make sure your feeding them a wide diet as well. They are omnivours like many cichlids and will do good from meaty foods as well as veggies.
No Feeders From the LFS. These feeders offer little to no nutrition as they are often not fed enough at the store, plus there is a high probability that they carry some contagious illness such as ich or fungus. Feeding them a diet that consists mostly of cichlid pellets (an engineered food that contains most all of the nutrients that they need) with treats of krill and veggies such as peas will help keep them very healthy and happy.
If the oscars will not readily accept a food you give them either... then dont fret and think you have give them only what they will eat. After about a week, they will start getting really hungry and then they begin to take the food you offer, even if they think they don't want it. And incase your wondering, a week without food will not harm them, they can go long stretches in nature without food.
Ox