Hi 'Nando,
Not to my knowledge. It's extremely rare to find such old things still loaded but the fact alone that these breeches are notably narrowed denotes that the ball must have been loaded separately.
In the late 15th to 17th centuries when small iron cartridges were used with breech loading long arms and hand firearms, they might have also contained the ball. All this is mere speculation though; I do not know of one single small iron cartridge that would still hold its load.
That should prove to all of us how little we actually know of these weapons.
Best,
Miguel