If I had a gun in the glove compartment, and a cop tells me to get my registration (which is also in the glove compartment), I would inform him there was a gun in there and then ask him how we should proceed.
How do you think the cop knew there was a gun in the glove compartment? They told him.
Nope. You're making that up.
Listen to the video again. The guy says, "Where at?" when he is told he ran a stop sign. Then, after the cop asks for his license (he does NOT ask for his registration), the guys says something about he had stopped at the sign. And then the cop screams about the gun.
The occupants never once mention the gun.
Listen to the video.