No, I don't think they did. If you look on the FDIC website I believe it says if you thought you held shares in Washington Mutual Bank, Wrong you actually held them in the holding company. I think it's just a mix-up of words actually.
Only debt holders I can think of the bank would be bond-holders.
All IMO and I don't have any factual information to back up what I said, if you do please correct me.