no its the type of pellets in the shells. with birdshot there are a lot more pellets in said casing since they are rather small (used for hunting waterfowl, pheasants and the like). buckshot are larger pellets (with varying degrees of sizings of the pellets, same with birdshot) therefore more killing power but less of them as well, usually used for hunting turkeys or larger birds. or in the military to kill people.
leading with this, pretty sure its safe to say it was birdshot due to the x ray shot that had a hundred or more pellets in his chest