There are 2 eprom types.
Base eprom which is particular to the slot theme. Uses a 27C4002 40 pin eprom. Labeled as SBXXXXXX.
Game eproms which is basically the OS for the game, most of the time, you don't ever have to replace these. Uses 27c801 32 pin eprom. Labeled SGXXXXXX. Usually 2 chips Game1 and Game2.
Optionally the S2000 had a Multimedia Daughter Card (Multi-Media Lite card) that used a proprietary IGT Simm module. Labeled as DSVXXXXX.
As the games got more involved, i.e. more than 9 paylines, they switched to a flash board scheme that contained a Base Chip SBXXXXXX and an Boot chip RBXXXXXX chip