An update to the R1 Sony DVD which I own.
The print on the DVD appears to be an extended US TV version of the film - it runs 97m rather than the 89m given by the UK BBFC to the theatrical release. The extra footage is the dire 7m prologue in which a newspaper reporter stands in front of various papers in his office and talks to the camera on the subject of Quantrill. This is interminable and also full of factual errors. The film proper begins with the voice over of the shots of Quantrill and his gang riding along.
The cinema print is shown occasionally on UK cable channels and doesn't have this sequence.