They wont be stored in the OPK. The save locations vary from emulator to emulator, usually it will be in first Micro SD Card in the emulators folder. For PCSX4ALL (PS1) emulator you can find it in /usr/local/home/pcsx4all/sstates/ The file names will be the game id i.e. slus01384.0.sav will be Castlevania. You can enter the first part in google and it should give the game name if you need to identify it.