I doubt if Poltergeist
used real skeletons and corpses -- it's so much easier and cheaper to get fake ones, and you don't have to worry about possible legal problems down the line.
One movie that did
use real corpses was Werner Herzog's remake of Nosferatu
. I recall reading about it at the time:
The opening sequence of the film, set to music by Popol Vuh, was filmed by Herzog himself at the Mummies of Guanajuato museum, Guanajuato, Mexico, where a large number of naturally mummified bodies of the victims of an 1833 cholera epidemic are on public display. Herzog had first seen the Guanajuato mummies while visiting in the 1960s. On his return in the 1970s he took the corpses out of the glass cases in which they are normally stored. To film them, he propped them against a wall, arranging them in a sequence running roughly from childhood to old age.
The film came out in 1979, only three years before [B/Poltergeist[/b]. I'll bet any money Spielberg was familiar with this case.