Nah, she should have kept her mouth shut, declared bankruptcy, pretended not to have the notes (no one knew) and had a clean slate with about $300K in the bank.
It might be hard to sell that many bills in the collector’s market without attracting a little attention. No guarantee that creditors or the government would have discovered it, but not the smartest thing to risk. Anyone who was upset with her for any reason could have tipped them off, and she would have faced jail time.