If an agency girl is Post OP TS they won't be making that clear to anyone IMO.
Buyer beware is the phrase to bear in mind, I would look at the most candid photos (if present) and make your judgement from those.
Once you arrive you also have another change to decide.
I will concur it is very hard to tell nowadays....with cosmetic surgery, tit and butt implements (by both genders)
If you unsure, dont book.