Long before I saw any of Leone's films (I started watching them in college during the mid-90s), my parents found an LP of the music from the first three films. But it wasn't the original music...it was all-new arrangements by Hugo Montenegro.
It was a fun listen, but after seeing the films, I was surprised how much was changed. Hugo's work was more of a "popular music" flavor...in fact, his rendition of "The Good, The Bad, and The Ugly" was released as a single. Now, let me clarify what I mean by "popular music": it was still an orchestra (Mr. Montegro's own, for that matter), but the music was presented as self-contained songs...and often with a great beat.

It's still a great album to listen to for nostalgia's sake, but in the end I prefer Ennio Morricone's originals.