Personally its probably just a time efficiency thing on bungies part: "what can we not model to save time for more important stuff? Hands and feet on the skeletons, people will run right by those." But...if it was done intentionally, some cultures throughout history have taken hands/claws/paws as trophies after hunts. Think shark teeth or bear paws...wolf pelts. That sort of thing. The fallen seem like a species that would have a mentality to do that to me.