It will never come back all the way on its own, that is a well established myth, if you just do one short cycle, AND you are lucky, it might come back most of the way, but the more you do and the longer you stay on, the more permanently lowered your natty production will be. PCT doesn't change this fact.
I will say this, IF you do decide to "cruise" on TRT, they you will REALLY be permanently shut down, so make sure you ready to marry the needle for the rest of your life. As one friend of mine put it, it's a permanently chemical umbilical cord.