[acg]

There are a few factory bumper guard versions. What is the model number for the guard?

 

[acg]

Try this:

Land Rover Discovery II Brush Bar - Product Instructions

 

[acg]

I have the 2003-2004 version:
DISCOVERY II (1999-2004) 2003-4 DISCO BLACK WRAPAROUND BRUSH BAR-Land Rover Rocklin-Niello Land Rover Dealer-California

Here is a pre-2003 D2 version (i.e., 1999-2002).... which matches your model number:
DISCOVERY II (1999-2004) 99-02 DISCO. BRUSH BAR, WRAPAROUND, BLACK-Land Rover Rocklin-Niello Land Rover Dealer-California

This is the D1 version of your brush guard:
DISCOVERY 1 (1994-1999) 1994-99 DISCO. 1, WRAPAROUND BRUSH BAR-Land Rover Rocklin-Niello Land Rover Dealer-California