As of right now there is no practical Way for CD’s to own and use any kind of Light source (except for Muzzle Flashes). There used to be a purchasable Flashlight at the Smuggler, however that was removed (It didnt even work anyways).
My Suggestion being, either return the Flashlight for the G18, so that Kingpins can use it → OR → add a functional Flashlight to the Smuggler/CD Vendor/Kingpin Vendor
In my Opinion every Player should atleast have a Opportunity to buy a Light Source.