How long did it take for them to peel it from a Hitachi? I can't imagine them removing it from any CCTV-equipped car! Not to mention the Hitachi sets were the last to retain the Zone 3 maps.
It's not even a proper 2000-era Connex map, look up 517M on VicSig and you'll come across one (I believe they also had north-side-only maps which only showed their six lines).
It will def be post 2003, esp due to Metlink being mentioned (due to them not starting til 2003..), and also end 2002 Connex took responsibilty for entire network.
The map in question began appearing on trains after the Connex/M>Train merger in April 2004
, with most being removed from mid-2007 prior to the extension of the Broadmeadows line to Craigieburn.
The particular blue and black styling which forms today's Metlink brand actually came to be under M>Train in Jan. 2002, with Sydenham (Watergardens) and Keilor Plains stations built with blue Metlink-style signage with the M>Train logo and minus the Metlink logo.
Further, M>Train had this map style without the Metlink brand when the Siemens sets were introduced, as per this image at VICSIG.