The shotgun is a weapon in the game that the player can use, however it never appears in the game's inventory, unlike the normal gun.
The back of the game box says that Lara will visit the 'Swamplands of New Orleans' however Lara never visits a swamplands or even New Orleans; the only locations in the game are New York, Teterboro airport (in an FMV) and the Backlin Islands in the Caribbean Sea.