I recently saw a Mark X 300g without the TRC off switch, currently looking to buy one, the owner claimed that it does indeed have traction. He was very frank and honest about everything, he also said that it can be confirmed by attaching computer and running diagnostics. My guess is it varies from car to car. Especially the 250 models don't come with traction, from what I understood after watching pw owner's review on youtube.
Hope that helps and best of luck!