No offense but we have no idea what you are talking about, ammo, weapon, revolver, pistol, baseball cap? Picture if you can, model number, barrel length if you are talking weapon, type of grips, type of sights? That number could apply to anything. Proof marks and any other marks you can find would be a help to us so we can help you.
Good intentions will always be pleaded for any assumption of power. The Constitution was made to guard the people against the dangers of good intentions. There are men in all ages who mean to govern will, but they mean to govern. They promise to be good masters, but they mean to be masters.