In a traffic stop, the first thing the cop does is look up your car reg. on his computer. If you are a CCW holder, it will show on his computer.
Depends on the state. Missouri by law in fact prohibits any information release regarding CCP by the issuing sheriff unless as part of a formal investigation/ court order.
MO used to collect & include CCP data in the MO Uniform Law Enforcement System (MULES) via department of revenue ( = DMV) but after the MO HP and the DOR gave the feds the lists of CCPs in breach of state law ( purportedly for SS fraud/mentally ill folks with a CCP and therefore likely a firearm), the state no longer actually knows who has a CCP-only the SD where you live- decentralized for privacy.
AFA how to act during a stop- be calm, keep your hands on the wheel , turn on a dome light before you stop, roll the window partly down, if you are carrying either tell the officer in neutral voice (I have a CCP and I am/am not carrying, it is on my left hip in a retention holster). Although in MO you are required to inform unless asked....
Do exactly as the LEO tells you.