Make sure you always use the same
USB port on the laptop. It will assign a different COM port if you use another USB port.
He was almost certainly lying/clueless. It is not straightforward swapping the centre consoles.
Other things to look at :
Heater/aircon : P1 basic aircon ( if fitted at all ), P2 climate control standard
Fuel cut off reset switch : driver's side P1, passenger P2
Carpet : This is different - both for the fuel cut off switch and a gap between the handbrake & tray on the P1 with a P2 carpet.
Engine bay relay location : on bulkhead on P1, right side inner wing P2
Fuel vapour recovery system : both boxes below the parcel shelf P1, 1 box in right wheel arch P2
Headlight flash : all 4 lights flash on P1, only main beams P2
As you can see, there are considerable differences between P2 & P1. That's a lot of change to allow an ECU to be chipped
and that list isn't comprehensive - just some of the more difficult things to change.
Just because it is a 1998, does not mean it is P2. The P2 only started production about September that year ( IIRC ) and there will have been unsold P1 stock lying around dealerships as well.