The Sniper Bug was designed by Jim Martin especially for Starship Troopers Deadlock. It is not present in any other Starship Troopers movie. The Sniper Bug kills from a distance by high frequency radio waves.
Commander Schroeder uses in the scene "Final Fight" a Morita Carabine. This prop shown in the movie is based on a Nerf gun Elite Longshot. It is operable and able to fire Nerf darts.
The "full face" helmet (M3-2) shown in the movie is an adaption between the M3 helmet and the helmets shown in "Starship Troopers Invasion" (animated). The prop is made real and it operates in both mode, as M3 helmet as known and by adding the face guard in closed mode. The visor of this helmet is operable and spring driven, no electronics is used.