De acordo com Lucas, sim.
No entanto, wookieepedia tem a dizer sobre o relacionamento em Splinter of the Minds Eye (o primeiro Star Wars Livro da UE):
At the time it was written, the familial relationship between Luke,
Leia, and Darth Vader had yet to be revealed. Therefore, some
inconsistencies are evident and unavoidable. Most noticeably the
sexual tension depicted between Luke and Leia in this book, which in
retrospect would be considered inappropriate in most countries.
(Although Lucas claimed to have had the Star Wars saga mapped out even
at this early stage, the fact that he allowed this plot element to
remain in Foster's novel has been cited as evidence that he hadn't yet
decided on the characters' true backstory.) However, Lucas has stated
before, that this tension was on purpose, to show that the two had
feelings for one another, but that they did not know exactly what type
of feelings.
Alguns antecedentes no Splinter:
Splinter of the Mind's Eye was the first-ever Expanded Universe novel
to be written and published. According to an interview with its
author, Alan Dean Foster, in Empire magazine, the novel had been
written to be filmed as a low budget sequel as a fallback plan in case
Star Wars hadn't been a huge success. This accounts for why the book
takes place almost entirely on a fog-shrouded planet. Additionally,
Harrison Ford was not signed for the sequel as of the writing of the
book, which is why Han Solo does not appear in it. Although George
Lucas is credited as the author of Star Wars: From the Adventures of
Luke Skywalker, the novelization of Star Wars Episode IV: A New Hope,
was in fact written by Alan Dean Foster. Foster's early involvement in
the Star Wars universe gave him the opportunity to write this book.
Though Foster was granted a great amount of leniency in developing the
story, one requirement was that a lot of props from Star Wars Episode
IV: A New Hope could be reused when filming the new film. According to
Foster, Lucas' only request upon inspecting the manuscript was the
removal of a dogfight in space undertaken by Luke and Leia before they
crash-land on Mimban. Presumably, this sequence would have cost too
much money to create.