The truth is Bolin wasn't even very well known in his own time. He may have had a local reputation around Forsyth as a thief and a bully, but if he had been even half as bad as the modern-day legend leads one to believe, he would have been well known throughout the whole state. Taney County may have been an isolated area during the Civil War, but it wasn't that isolated. Confederate guerrillas like Tom Livingston of Jasper County were well known in Union circles at least as far away as Kansas City and St. Louis, and Livingston was often mentioned in official Union and Confederate reports. Bolin, on the other hand, who was supposedly more heinous than Livingston ever thought about being, receives not one mention in the Official Records--not one. There is one brief mention of a horse thief named Boler in the Taney County area that may refer to Bolin but nothing specifically about Alf Bolin.
Because Bolin was not particularly infamous, very little was written about him until after he died, and because of this lack of a written record, it's hard to go back and disprove the legend. In at least one instance, though, the legend can be discredited by available written records. Bolin is usually blamed (or given credit for) the murder of Old Man Budd in southern Christian County. Written records at the Missouri State Archives show that this incident occurred during the late summer or early fall of 1861, and the leader of the gang who committed the murder was not Alf Bolin. Bolin may have been among the gang, but he was not its leader.
The main reason Bolin became so legendary and notorious after his death was the way he died and what happened to his body postmortem. He had the misfortune (or the good fortune one might say if he was aiming for immortality) to get his head chopped off.