How to recognize if 16mm film is silent or has sound
Original 16mm film usually does not have sound. Sound is added to the film at a later point. So, original 16mm negative or reversal film will not have sound, and it will usually have perforation holes on both sides of the film.
One can visually detect if 16mm film has sound by looking at the edge of the film. The film will only have perforation holes on one side, and would either show an optical sound track (a squiggly transparent line on top of a black background along the edge of the film), or have a strip of magnetic tape affixed to one edge of the film.
Super-16 mm single perf film (perforation on one side) does not have sound.