As I was kid "La guerre des étoiles" always refer to the first movie (EP4). I don't know how is it now with the young people. Are they talking about "Un nouvel espoir" (A new hope) ? Perhaps...
In fact "La guerre des étoiles" is a bad translation.
"La guerre des étoiles" is the traduction of "Stars War"
The correct traduction "Star Wars" is "Les guerres de l'étoile".