Zach is the ultimate authority on these PCBs, but according to the Wiki page at [
www.reprap.org]
the 1.2.1 boards have no known bugs, so that would mean no, the TG connector does not need to be flipped on them.
It should be fairly simple to check by inspection of the traces, since the G connection will go to the ground plane for both TG and RG connectors, and the T and R connections go to the PIC. Or, just wait for Zach to confirm my theory :-)
Jonathan