you can tell which annoymous is which by car skin
I just went through the maps and this is the finishes if my thoughts are right: Anonymous Lime has finished all the maps, Anonymous Blue/Gray has finished 2 maps: anonymous Gray/Yellow has finished 3 maps, Anonymous Blue has finished 3 maps, Anonymous Gray has finished 4 maps, Anonymous Dark Green has finished 1 map, and Anonymous Pink has finished 2 maps
The thing is that the colors aren't randomized, wich means there could be more of the same colors, like here: