I wasn't able to find much information on the discovery of Richard III's skeleton other than a short story in BBC and Yahoo news. They both confirm that the skeleton they found had a barbed arrow head lodged in its back which occurred at the time of his death. "A university spokesperson said the evidence included signs of a peri-mortem (near-death) trauma to the skull and a barbed iron arrow head in the area of the spine." from BBC news.
I'm guessing Richard III would have been wearing the best armor available. Is this real-world evidence of a warbow arrow penetrating armor in a battlefield situation? Maybe the arrow was shot from a crossbow? The story of his death, from what I've read, describes him being pulled from his horse and killed with a blow to the head. Maybe he was shot in the back after his death? Anyone have any thoughts?