That has happend with various films, the 1989 Tim Burton Batman had both a score album (Danny Elfman), containing all the beautiful and powerful scores ranging from the main title, to charge of the batmobile all the iconic music you heard is there on the score cd.
Now seperately to accompany the score was all the music by Prince.
The Fast & The Furious had two albums but that was more aless to get in all the sheer volume of music in, there was the main theme added in one of the albums, cant remember which one, I have them but havent listend to them for years.
I very much doubt Knight Rider would get two releases, even the recent Miami Vice soundtrack didnt get that, they had both elements added to the cd, songs and scores so I would imagine thats the way they'd go.
It worked for the Miami Vice one, if you havent got it, highly recommend it.