I would draw a distinction between those who pass and those who don't rather than those who have had any particular surgery versus those who have not. Relatively few who pass are out and open about being anywhere on the trans* spectrum, regardless of whether they have had SRS. Those who don't pass, on the other hand, have little choice about being out or not. Again, regardless of whether they have had SRS.
SRS itself is something that gets a huge amount of importance in many people's minds. I am not knocking that because for some it truly is the end-all-be-all, for others it is irrelevant, and for most it's somewhere between those extremes. And that's fine. But in terms of blending in day to day, its importance is relatively low because it affects body parts that are or ally covered.
And of course the above is only in response to mtf spectrum SRS. For ftm spectrum individuals, the question of "what surgery do you mean?" gets all the more complex. Mastectomy, for example, affects a persons blend ability a whole lot more than phaloplasty because it affects something visible and alleviates the need to bind, which eliminates the need to choose between breathing and passing.
