From http://news.techwhack.com/2506/20111...-based-plants/ ...

General Motors might close four US based plants

General Motors might close four US based plants

Market sources claim that the Chief Executive of the world’s largest automaker General Motors Rick Wagoner is due to announce company’s plan to close around 4 of their United States based car production plants. The announcement can come anytime this week itself and the reports quote a company insider for this information.
The AP version of the story is here: http://newsok.com/article/1646137/?template=home/main

I've not been able to locate anything yet which identifies or speculates about which plants, but I suppose that the OKC plant may well be a possibility.