CZ27 EK police rig

[sheepherder]

Although these seem fairly common in my area (a friend in high school's father had one he brought back from WW II), I'm not familiar with them...What exactly makes/identifies the pistol (not the holster) as a Police CZ 27???

There is one at my LGS (minus holster); I'll be going down there later and will check it for Police markings...Whatever they are...