Yes. Open carry is illegal in Denver and from everything I've seen he was carrying openly, with a tucked in tshirt. From the videos he's lucky he wasn't charged with resisting arrest.
I never open carry here in Colorado because it scares the spineless hipsters. When I got my CCW back in Nashville when they first made it legal the cops were looking for ‘printing’. They really didn’t like the idea of ‘civilians’ carrying weapons. I even had a Nashville cop (a real scholar) tell me I couldn’t carry a weapon inside the business I was working at.