You will need to contact them directly to find out this as no one here works for them and does not have access to the technicalities of what they use (unless you're lucky and someone has asked that question)
It has been asked a few times and the answer in the past, for the 3600mhz RAM, was CL18. You would need to call/contact to confirm though as stock does change frequently. I think given that the price is the same between the 3200 and the 3600 it would suggest to me that it's definitely the CL18.