"I bought the complete set several years back for $500 and was told that this was the only set he had, now the set might be worth $100 due to the greed of people yet to be named by anybody."

You might be the victim of something all together different.
Several years you might have been told the truth.
The hoard was found and lied about, not too long ago.

New chips being found is the a chance we all take.