And because Sega ST-V is SuperH architecture, which is Big Endian, it doesn't need its byte swapped?No swap needed. There is little endian and big endian type of CPUs.
https://en.wikipedia.org/wiki/Endianness
But how can you tell if your to be flashed .bin is ready for big or little endian?Endianness is the order of the bytes that compose a digital word in computer memory. It also describes the order of byte transmission over a digital link. Words may be represented in big-endian or little-endian format. When storing a word in big-endian format the most significant byte, which is the byte containing the most significant bit, is stored first and the following bytes are stored in decreasing significance order with the least significant byte, which is the byte containing the least significant bit, thus being stored at last place.