The first time does tend to be a "Getting to know you" session, sort of one sided. But you said you emailed some beforehand. So some to a lot of the background stuff may be covered. Plus you are likely filling out a ton of papers answering all sorts of questions.
As far as HRT goes..... I am speaking somewhat out of my arse not having a lot of hard facts, just some observational/anecdotal data. There seems to be 2 sorts of TG therapists, the "Rubber Stampers" (my term) and the ones that want to be reasonably sure you know enough not to making a big mistake. After having been to the Maryland State Senate hearings on the TG Rights bill that eventually passed, there are those that likely should never have been given the go-ahead that the opposition trotted out. The Rubber-Stampers just want to make sure you are basically OK and will give you the CYA letter.
Full-Disclosure, I don't believe in GateKeepers, and the reality side of me knows all too well the Need for a CYA letter. It's a game to keep the lawyers away. What isn't a game is not being totally honest with a therapist and saying or doing what is necessary to get what you want.
So..... Your therapist just may have heard enough of the right stuff to feel comfortable providing the letter. The office visit a mere formality and tie up some loose ends.