Other way around I think.
The switch over from fixed screen to adjustable height screen is listed as taking place in 2004 but I don't know if there were K4 models with both types, or even if a 2004 plate bike could actually be a late registered K3 bike. Here's a list of the K4 changes in case it helps.
2004 (K4) Redesigned instrument cluster. Upgrade 16-bit to 32-bit ECU, some sensors changed. New turn signals, 20 watt without reflector compared with earlier 10 watt. Belly pan redesigned. Stronger hand guards attached to end of handlebar. New adjustable windscreen design. Left handlebar switch incorporates flash-to-pass & emergency blinkers (EU models already had this). Stronger handlebars. Revised mirrors for less mirror breakage.
Either way, that cowl is from an earlier bike with a fixed height screen and that screen is for K4 onwards bikes with the adjustable height screen.