I think you misunderstood the setIdentity command.
The "Cop (M9 Pistol)" is the description for the unit given by the addon maker. It will never change, no matter what you try because it's in the config of the addon.
With setIdentity you only can overwrite:
- The random name given to the unit (shown in dialogues, chats etc)
- The Face and glasses
- The voice and pitch