Or are they removed to fit more gear?
Usually just a stock AM-FM radio, no tape. Cops like to listen to the radio too. The easiest way to tell if a police car has a radio is look for the antenna.
I was once in a police car whose operator had retrofitted it with a kick-ass stereo for those long patrols.
It was in a suburban jurisdiction where the officers took the cars home at night and spent almost the entire shift in their cars, so YMMV.
Most of our ambulances had basic AM/FM radios but we were flat out forbidden to use them unless another little toy was on them. several of them had a unit that patched into the stereo speakers, whenever anyone keyed up the med net radios it muted the stereo so you could hear the radios clearly.