I can offer no rational explanation other than Italian tuneups may be as effective today (for emissions) as they were in the old days.

Given this car's relative low mileage for its age it may have have seen a lot of short trips, and it's possible that habitual short trips can temporarily foul the catalyst due to rich operation during warmup.

For a modern Italian tuneup avoid WOT so the engine stays in closed loop operation, but use aggressive acceleration and revs with no more than 3/4 throttle travel.

Duke