I think the OP is lucky he didn't go to jail for "brandishing" a gun. I hear a lot of stories on the new where in a road rage someone flashes a gun and get felonies.
I have the belief that flashing guns to stop fights is stupid and dangerous. IMO Never pull a gun unless you intent to use it. just MO.
You are in a fight in fights people will use any available tactic to harm you including calling the police which happens very often when guns come out. They risk getting petty offense "disturbing the peace" you risk a felony as soon as the gun comes out.
Maybe the guy also had a gun and now he has the advantage of shooting you while you are stuck inside the car with limited movement. He will probably say something like "He pulled a gun and said you are going to die". Your word against his and you are dead.
I don't carry in my car that much, when I do I also have a jacket or sweat shirt in the seat by me so if I need the gun close it can still be hidden. I always though that if someone did attack me while I was in the car I would get the gun cover it and wait for them to break the window and fill their cheat full of rounds. That is the idea, but in real life who know how things play out?