They are just outfitting them with really bad laser site choices.

The prop guys said they did it deliberately to make the guns look futuristic and, unless you're retarded - or very new to the planet - you can see with your own eyes that's what they were trying to do.

laser sites were very popular and trending at the time

Cops didn't have even properly matched laser sights on their handguns in 1990, that's why the prop guys were able to successfully produce a futuristic look just by adding mismatched laser sights. Additionally, the Desert Eagle already nearly had a futuristic look to the general public - especially in the hands of a cop, unlike the SIG which required a greatly mismatched, bulging laser sight to produce the futuristic look.

Those are actually real guns, available at the time

99% of the general public doesn't know these are standard weapons any more than they knew Han Solo's blaster was a modified Mauser.
You clearly don't know how much the prop guys know the general public doesn't know.

They weren't going for a distant future look, but they were going for a practical future look and they believed it was likely that in just 7 years cops would already have more futuristic looking weaponry. That's because 7 years used to be a really long fucking time. Disco to Debbie Gibson was just 7 years. A four-year Presidential term used to be an eternity. People had given up hope that Back to the Future II would ever Be Continued... after just 3 years had passed. In contrast, in 2023, seven years is like the difference between being able to run a PC game on medium-high settings instead of medium settings. When a publisher announces a game to be released in 5 years, people respond as if they said 2 years and they start preparing to put in their preorders. 36-year-olds now have the mental maturity and wisdom that 26-year-olds had in the 1980's.
Like it or not, something has modified the way most humans perceive the passage of time. Presumably EMR, something in the screens we stare at all day or something in the 'energy saving' lights they desperately wanted us to switch to (at a profit loss even).