The Hollywood studios claimed they had stockpiled something like 50 “ready to shoot” scripts before members of the Writers Guild of America (including Diablo Cody) walked out last week, but Anne Thompson and Tatiana Siegel cast doubt on this in this bargaining ploy in a piece for weekly Variety. “There’s no such thing as a locked script,” they quote one producer as saying, and offer estimates that as many as 75 percent of these supposedly ready-to-roll projects (including the sequel to “The Da Vinci Code”) could be up in the air. Some have incomplete casts, and big-name actors tend to demand now-unavailable script tweaks before signing on to the project. Ratcheting up the pressure is the studios’ determination to shoot a year’s worth of product before the actors’ and directors’ contracts expire next June.