OST = VINYL = SCORE INTERPOLATION, essentially for reasons of personal aesthetics and enforced truncation by way of necessity due to space restraints/consideration?
The original film score recording = THE FIRST IMPRESSION committed to both paper and celluloid. The long march.
I've been listening to this enjoyable score recently, & I was wondering; the last track on the second disc, Guitar Strums / The Sweetheart Tree (alternate vocal)...is that alternate vocal Natalie Wood? The booklet is very careful not to mention who the singer is (probably a contractual thing). The voice is a bit rough, like from a 40 a day smoker.
...ah! I've just read a few posts above, & the consensus is that it is Natalie.