The pin spots on the hard top aren't unheard of, it's something to do with the aluminium reacting, my Range Rover which has ally panels suffers in the same way, and I have seen a couple with rusty front wings.
The panoramic roof suffers from edge corrosion - both of mine were painted under Mobilo.
The 1999MY cars were available from 08/98 - there are some pre-facelift cars on T-plates that cross over.
The aircon unit mentioned earlier is something I've never resolved - a few 1997 cars have them when in 1996 the newer unit was introduced. Old stock being used up?