The Doedicurus does not have multipliers for headshots or any other areas.
Note: The Doedicurus can gather Obsidian from a small number of rocks, such as the ones on the volcano on The Island. It cannot gather Obsidian from most usual Obsidian rocks.
What does a Doedicurus eat? In Ark: Survival Evolved, the Doedicurus eats Kibble, Crops, Mejoberry, and Berries.