The following weapons were used in the film Jurassic Park:
A Franchi SPAS-12 is used by Robert Muldoon (Bob Peck) and Professor Alan Grant (Sam Neill) over the course of the movie, also seen in the hands of several InGen workers in the introduction and in the gun lockers. It is last seen lying discarded on the computer room floor after jamming due to a stovepipe malfunction when Grant used it to try to fend off an attacking Velociraptor.
The M16A2 is seen carried by several InGen workers in the beginning of the film and is stored in the gun lockers in the emergency bunker. Most of the M16A2's carried by the workers can be seen fitted with weaponlights mounted on the barrels ahead of the front sights.
Some of the Ingen workers are also seen with 'slab-side' M16 rifles, or possible AR-15/SP1s. Then again, they could be simple rubber props modeled after said rifles. They are fitted with A2-style handguards to pass for an M16A2.
Robert Muldoon (Bob Peck) also appears to carry a pistol in a black leather holster with "US" marked on it, which usually means that he keeps some type of M1911A1 as his sidearm. Muldoon isn't seen pulling this weapon in the film.