I was on T 3years before my surgery, my T levels had always been on the low end. After the surgery, they have still been pretty low, not noticed any physical changes or changes in levels.
My T dose has finally been increased abotu 2 months ago, so about 7 months post op, and up until then, things have seemed the same as pre surgery.
I hope that helps.
Edit: Just to add, I never had to stop taking T, but Im on Nebido, so I dont know if that makes any difference...