Continuity mistake: The speech that Moore claims/shows then NRA president Charlton Heston giving in Colorado is actually several speeches edited into one. Note how Heston's clothing changes between cuts during this speech.
Continuity mistake: After interviewing Charlton Heston and as he is leaving Heston's property, Michael Moore tries to show him the picture of a little girl that was killed by her 6 year old classmate. Heston walks away but Moore keeps shouting back to him. The scene keeps jumping back and forth between a wide shot behind Moore looking into Heston's yard, an a very close up shot of Moore as he is yelling with the picture to show Heston. Moore claims both angles were taken simultaneously with two cameras. However, neither camera is visible in the shots. This is impossible. In the wide shots, there is no place that the close up camera could have been hidden. Due to the plants, etc. obstructing the view, the close up camera had to be a few feet in front of Moore at most and thus would have been visible in the side angle shots.
Answer: The song sounds very much like an acoustic guitar version of "Beecher's Lament" by Jeff Gibbs, who is credited with composing all original music for the film, including this song. A beautiful, haunting piano dominated version of this song appears on his only CD "Reflections". The song can be sampled at Jeff Gibb's web page. Link provided http://www.jeffgibbs.com/music.shtml.
OneHappyHusky