They like to clip them down to the A Pillar driver's side. Makes it low profile. There's a notch in the pillar. However looking back I may not have been looking at a Charger, since those antennas are center cab mounted I thought? This one had a ball mount on the rear driver's side if I recall, possibly a Camaro but I thought those were flushed through the fleet.
Here in Sacramento, the cars assigned to the Capitol Protection Section almost always have their antennas clipped, as @norcalscan mentioned. They can still transmit on the low-band when they help the freeway units.
Some of the chargers have a "low profile" antenna on the right rear quarter panel that looks like an OE-style antenna. It's not that noticeable unless you're looking for it, one of the head honchos out of the Santa Maria office runs a dark blue unmarked Charger.
Once you see it, you'll recognize that it's a bit larger than normal.