My old 03 V6 had that.
The big change was in 01.
99 - Clear Head Lights, Same interior layout as the 98s, 35 Ann. Badges, 16" Standard Wheels (opt. 17" Wheels), Spoiler
00 - Same as 99 - the 35th Ann. Badges, No Cobra, 300 Cobra Rs made
01 - Added Hood Scoop, Different Side Scoops, Different Spoiler, Smoked Headlights, New interior layout, new Stereo Head Units, Bullitt Released, Cobra rereleased with different Seats (Suede inserts).
02 - Bullitt Wheels offered as an option on GTs
03 - New Cobra Released, Mach 1 Released, 100th Ann. Cars released (special side badges), V6 gets the 99/01 Cobra Hood
04 - 40th Ann. Badges, 40th Ann. Package offered (special Red color and Racing Stripes)
I can't remember when Ford started offering the Interior Upgrade Package. I assume it's in 02 after the Bullitt was released as it features the Bullitt Pedals, Bullitt Shift Knob, Bullitt Shift Bezel, and Bullitt Door Lock Pins.