Yes, they do, but even in the early days GL might not have had the time to actually read all of it. Marvel was given a laundry list of "no no's" from Lucasfilm when they finished the movie adaptation and did original stories. The Luke/Han/Leia triangle could only go in circles, and for a long period, they couldn't do anything with Vader at all. I imagine Dark Horse and other literary licensees have similar restrictions.
It's one of the reasons the Marvel team concentrated on Han and Chewie having their own misadventures on the way to pay back Jabba. In fact, they get robbed by space pirates of the reward money for rescuing Leia right off the bat!
With the exception of Splinter of the Mind's Eye, all the early novels focus on Han or Lando.
Marvel was able to do some flashback stories about Luke and Biggs, and even an tale about Obi Wan in his Jedi days that could make for a good CW episode with a slight rewrite.