These guys aren't straight. They do want pre-ops or CDs for that something extra. And what's so sad about this, are the CDs who fool themselves into believing these admirers are treating them like women.
I've learned a lot from Alice (Richard) Novik, author of "Alice in Genderland". She's a psychiatrist, unapologetically trans (both genders ... for now. She does not discount future changes), and in an open marriage with a GG. She is also unapologetic about the sexual aspect of being trans.
This is what she has to say about admirers:
http://aliceingenderland.com/Manhunt.html
Alice knows that many TSs criticize her though, because she does agree with the concept of autogynephilia (which she says is heterosexuality turned inward), although she does speaks of AGP more in terms of how it affects CDs than TSs. Her entire site is well worth reading:
http://aliceingenderland.com. She has recently come out with a revision of her book.