I can't comment to the accuracy of this particular reproduction however there are several prehispanic Mesoamerica wind instruments that have been called "Death Whistles." While it is likely that these instruments were used for ritual purposes, the specifics of their usage are not known. It is certainly true that instruments played a part in battle, specifically drums and shell instruments, I can't say I've vread of hundreds of these whistles being used as a prelude to war.

EDIT: I see MexicoLore put out an article on this, they're usually pretty good for introductory information: http://www.mexicolore.co.uk/aztecs/music/death-whistle