"I heard that he went into the vault the night before the place went boom with employees!"

That never happened.
The chips were part of the estate in a bankrupsy court action. They were sold off.

Bill Borland can be thanked for that happening.
He sued in federal over the Thunderbird chips and won, after gaming ruled they had to be destroyed.

My guess is the Stardust chips will be destroyed since Boyd Gaming will still be in busimess in NV.