I did most (not all) KP missions back in the day. I even did UK and France when it was in beta test mode. (I'm old!) On my last trip, my daughter and I did five Agent P missions, including UK and France. As the previous poster indicated, some of the clue mechanisms (such as the golf ball) are the same, but the story lines are completely updated and some of the effects are new.
Even with the KP missions, you could do the same country multiple times and the plot would be slightly different. The computer controlling the "mission" disperses players and gives slightly different experiences to each team, so they were somewhat repeatable.