It sounds like you'd expect. Strummed acoustic guitar, electric guitar with reverb and lots of attack. The occasional harmonica. Sweeping themes on the trumpet.

In other words it's an example of the subgenre of soundtrack music for which Ennio Morricone is famous.

Trovajoli comes up with some melodies and atmospheres all his own, however, such as the eerie, organ-drone cue for "Dopo Il Duello Part 2".