....and in the previous books what clues does king give us to make us believe that roland may know he's completed his quest before? I'm asking for specific or paraphrased lines (or book and page numbers if it do ya well).

I'm guessing roland first got to the dark tower when he was around 35 based off what we know when Shemie's being described while he's with Ted and Dinky and they're meeting rolands new ka-tet in the cave outside of breaker village in Book VII. Whatdoyouthink?