FFDO's carry a .40 cal HK USP compact with the LEM trigger. The LEM trigger still uses a hammer, but the spring is partially loaded when the slide is cycled. Somewhere around a 6.5 lbs trigger pull.
As far as it being unholstered, it is supposed to be holstered in an issue holster. Recently FFDOs were being issued a new holster that had a slot to insert a padlock for transport.