Direct from Carbotech FAQ section:
If you have had another manufacturers brake pads on those same rotors; then you will ABSOLUTELY have to replace or resurface (turn) those rotors before installing the Carbotech brake pads.

If the rotors and drums are in relatively good condition, meaning they are smooth, flat, with no visible cracks, deep scoring, distorted, and with no other visible damage; and you have ONLY had Carbotech brake pads on them, then they do not have to be resurfaced or replaced.

Carbotech RP2
The RP2 compound was engineered for endurance racing based on our highly successful XP Series formulations. RP2 is our longest lasting compound that we offer. RP2 has strong initial bite, a little less modulation than our XP12, but still maintains the rotor friendliness of our XP series compounds. With a good initial bite and one of the most consistent torque curves in the market the RP2™ compound is easy to keep a consistent bite and torque throughout the braking zone. Great fade resistance with a temperature range of 250°F to 1650°F+ (121°C to 898°C). RP2 is as rotor friendly as our XP series compounds. Carbotech RP2 is NOT recommended for use as a daily driven street pad due to possible elevated levels of dust and noise.