Yes, S12G64 is specified as a supported derivative in SSD driver (there isn't any difference in NVM operations between "G" and "GA" versions). The derivative configuration is made by FLASH_DERIVATIVE macro. Please look at chapter 2.4 in SSD driver user manual.
No, there isn't any specific function for EEPROM or Flash read. You may read these memories the same way as RAM. So, you may define and access data as variable/constants or you may apply a simple read function via a pointer. For example:
address = 0x000B00;
result = * ((unsigned int*) address);
I hope it helps you.
BR
RadekS