Ah, ok- had me wondering a bit. The gold disc with the 1996 Maxis copyright would be the original release of the game. The other would most likely have been a later print or possibly a Greatest Hits version. The game on them should still be identical, the only difference would be the cheaper paint job done on the later disc. The slus-00113 and slus-00113gs are the code numbers for the games in Sony's SKU listings.
The first disc's problems may have been due to scratches on there making it unreadable.