Dash Cam Footage of Bobbi Kristina's Boyfriend's Arrest Goes Online

In the video, Gordon tells the police officer he keeps a 9mm gun in his glove box. The cop checks it out after putting Gordon in his cruiser, and based on the video, it appears the gun is legit.

We broke the story ... Nick was popped in Alpharetta, Georgia last week just after cops say he was going 82 mph in a 35 mph zone near a pedestrian-jammed shopping area.

You can see in the video, Gordon was driving a Chevy Camaro -- the same kind of car BK was driving when she crashed into an embankment hours before Nick was arrested.