No mention of Vegas, and it was mainly just small talk before they began discussing the costume. Selleck joked that the costume sounded like such a bad idea, he couldn't help but endorse it. When he mentioned he never received any money, I kept waiting for Conan to point out the obvious- that they probably haven't sold any yet.
When discussing the actors (and George Clooney), Selleck added, "To George's credit, he did come in second place." Conan asked who was first, to which Selleck just smiled and said, "I was."
John Stamos was the second guest, and Selleck hung around for his interview. Stamos admitted he doesn't like to do shirtless scenes because he is self-conscious about his bellybutton. When he was a child, doctors had to operate on him and did a poor job when stitching him up. As a result, the scar created a slight bump which Stamos described as "a little nose". (The skin on top kind've hangs over the bottom half.)
Obviously, Conan said he HAD to see it. This led to Selleck, Stamos, and Conan all standing up to bare their bellybuttons. Since Stamos' bellybutton did protrude out like a little nose, Selleck suggested they put the Magnum mustache (from the costume) under it, which they did.
As you can imagine, there was a lot of Magnum's trademark laugh during this entire sequence.