It seems that for CN maps the mapID depends on the version number (or Product number) too, for example:

City Navigator Taiwan NT
2012.10 (v12.10, Pr: D287507AG030) - FID/PID: 2611/1 > mapID: 5321545 (513349)
2012.11 (v12.11, Pr: D287507BG030) - FID/PID: 2611/1 > mapID: 5323598 (513B4E)