Undead Lore: It came up as an option during the play test. In my original draft, you couldn't determine the information at all. The problem is they have no real forensic science, so no basis of scientific fact for determining things like whether a wound is post mortem. A person can be observant, but unless they have practical knowledge of how a dead body takes wounds differently than a live body, that doesn't really help. Someone with a good Undead Lore probably has put some thought into that, or has practical experience with wounding dead bodies.