The 503CW was made in a Red leather with Gold plating for the 50th anniversary, only 500 were made. they will have a gold engraved plate on the side.
There were a couple (50) of Blue leather 203FE's made that were for auction only.
There were two made for King Bhumibol, of Thailand, that were black and golf with a royal crown emblem, but i doubt you're looking at those.
Silver/grey were for the Apollo mission, and there were a few made later to commemorate that.
Other colors, to the best of my (limited) knowledge, are regular camera bodies that have had their leather replaced with colored leather. You can get some at cameraleather.com.
There may have been other Hasselblad-produced with colors, but I can't figure that out with any certainty.