Doesn't seem to have changed the cable at all, no. The only mechanical changes I can find anywhere, and I've looked quite a bit, are strictly to the electrical male pins on the device side to improve contact on the current carriers and shorter sense pins as to prevent operation if the insertion is even a tiny bit incorrect- everything else was kept the same as to maintain mechanical compatibility between the two specs.

PSU makers rebranding cables as 12V2x6 is probably just a marketing/keeping up with the spec thing. It should also mean that they changed the pins on the PSU side as well for modular power supplies.