Wow, those are complex questions
Short answer – maybe.
Long answer: There are 26+/- intersex conditions; some would require surgery and some would not. It's too broad of a category to make more than basic observations.
Surgery used to be (and sometime still is) conducted on the infant in the first few months of life. Now, where there is doubt about the sex, it happens at two years or even older. In some cases, there would be minimal scarring or scars that would fade away, becoming invisible, in other cases, there would be noticeable scars even much later in life.
If a person had a definitive genital defect during adolescence that required surgery and had had a feeling of being the wrong sex, that would be highly indicative of a link. It would not establish the link. Many people born intersexed and "assigned" a sex seem quite happy with the assignment. Many are not happy with the assignment. Noticeable deficiencies in testosterone levels are, by themselves, not definitive for anything particular and there are a number of intersexed individuals that go through puberty without any problems what so ever. It all depends on the specific condition and the severity of the condition. The number of conditions and the varying symptoms of those conditions would mean that a person may never know or a person may learn of it during puberty or they may learn of it later in life.
I can say from experience, the doctors and the psychologist have separated my condition from my dysphoria and for practical purposes are treating them totally separately. Surgery will be slightly different but not bad. Transitioning from male to female seems much the same. I have 95% of the same problems. I consider myself to be female who would be under the transgender umbrella. Some intersexed people who identify as the assigned gender do not identify as trans.
From my experience, the intersexed "community" does not like trans folk. At all. They also do not welcome me. At all. Here, I have found a home and although slightly different, am far more similar than I am to most in the intersexed community.
I have a link to a really good 1-hour special on intersexed people that I will post once I get home.
Wishing you well and a happy that things seem to be going better (I do read your posts but do not often respond). You stuck with it when I would have run. You are amazing.
Hugs,
Jen.