You do have to close, btw. Otherwise, you will always have a risk out there.
No. There would be some risk if the stock had simply had its registration revoked, and the company then went dark. In that case, however, the stock would still exist. And sensible shorts would cover, just in case a custodianship player came along and picked up the shell.
But that won't happen here, because the common stock has been cancelled. Extinguished. Bereft of life, it rests in peace. It is an ex-stock.