“As Mickey turns 80 this fall, the most beloved rodent in show business is widely regarded as a national treasure. But he is owned lock, stock and trademark ears by the corporate heirs of his genius creator, Walt Disney. Brand experts reckon his value to today’s Walt Disney Co. empire at more than $3 billion.” But “film credits from the 1920s revealed imprecision in copyright claims that some experts say could invalidate Disney’s long-held copyright, though a Disney lawyer dismissed that idea as ‘frivolous’.”