King Kong is public domain.
Technically kind of true but not really.
The rights to King Kong is complicated.
1. Warner Bros. owns the rights to the original film. Ted Turner acquired KING KONG when he bought the RKO film library in 1986. His company merged with Time Warner in 1995 and his films became part of Warner Bros.
2. Merian Cooper's estate sold Universal rights to the character and the plot of KING KONG, plus the theme park and certain merchandising rights. This allowed Universal to do their own KING KONG remake in 2005.
3. The Cooper estate retained publishing and some other limited merchandising rights.
4. The 1933 novelization has fallen into the public domain because the copyright was not renewed. This is the only aspect of KING KONG that is in the public domain. Anyone can publish the original novel but that's all they can do. In 2005, Cooper's estate published a new novelization of the King Kong story to establish a new official version.
So, in 1993 Turner would have controlled the 1933 film and some licensing rights connected to it (home video, toys based on that particular film, etc). But if Toho wanted to use the King Kong character in a new film they would have needed to make a deal with the estate of Merian Cooper. If they wanted to make a film now (which they don't), they'd have to license the rights from Universal.