I have booked in for acupuncture from 37 weeks, and the girl I am going to does more to prepare the body for labour for the first few sessions, and doesn't do any inducing methods until after 41 weeks.
So I guess there are different ways to do it, I suppose depending where the needles go etc.so speak to the person you are going to see and just clarify with them they are not doing anything to induce labour, and rather to prepare you for labour.