If V1.2 have LFrame connected on Pin 3 of LPC bus, and V1.3 have not LFrame connected on pin 3, simply measure with multimeter, setting it on "diode test", from GND to pin 3 of LPC bus, red on GND and black on pin3.
If V1.2 you will read about 0,5-0,6 Volts, if V1.3 you will read "infinite" (pin disconnected).
Simply, like GND measurement for V1.4 - V1.5.
Obviously, X-Box must be off.
Is an alternative to serial checking.
Sorry for my English, i hope you understand.