Remember the first Terminator movie, when Arnold Schwarzenegger used a handgun with a laser sight? That was in 1984, back before laser gunsights became popular. In those days, low-cost lasers were still helium-neon filled glass tubes requiring high voltage (and “low-cost” was hundreds of dollars).
Recently, gear site Ars Technica ran into the designer of Terminator’s laser gunsight, a man named Ed Reynolds who is with SureFire, a company specializing in tactical flashlights. He related how, in 1978, he had put a laser on a .357 Magnum for SureFire: it was “very expensive, and we highly modified the weapon”. For the 1984 movie, he made two props. One used a working laser on top of an AMT Longslide handgun. There was a hidden cable that ran up Schwarzenegger’s coat sleeve, to a power supply and a switch hidden in his non-gun hand. Arnold himself had to turn the laser beam on and off.

The second gun was a non-working prop without the wire.
Although the gun became an icon (it was used in the movie’s poster), Reynolds only got a few promo items for his trouble. Oh, and a credit at the very end of the movie. Fortunately, he has a good attitude about the experience, noting “I got to benefit because I could say, ‘Hey, I did that!’”
For laserists of a certain age, it is a reminder of the day when lasers were a lot more exotic and difficult to use, and when seeing a real laser beam on-screen was rare.