Each of the bullion bars should have a stamp of authenticity engraved on them. This will give you all the vital information about the purity and the standards of them. This is very important for those people who are more into collections and not as investments.
You are probably aware that most precious metals have worth around the world. Looking at them from the surface, they really have no day to day value for us. Silver or gold is never going to help you to live your life on the day to day so you would think that they would have very little value to us.