From SA-MP Wiki
"Hidden colours are not synced and most of them are different on each connection to sa-mp server. This leads to "situations, when each player sees different colour on the same vehicle at the same time.
Is this still an issue. In previous versions of samp this color sync issue occured for all colours. On 0.3 this issue was fixed. So did hidden colours somehow not get fixed with the full colour sync fix? Mansonh 18:55, 14 February 2010 (UTC)
In fact they were never synced except of first few testing 0.3 versions :) . User:Vojtas CZ/sig 21:56, 14 February 2010 (UTC)