This article seems to indicate the exact opposite; that the new Pro displays (including the 13") have markedly improved colour accuracy. "Colour accuracy in the three MacBook Pro displays is as right as we've seen in a laptop display, equal to or better than some midrange desktop displays and not that far off the level of colour correctness found in a premium desktop display." http://www.robgalbraith.com/bins/multi_p…
Color accuracy isn't so much color resolution. That's like the difference between precision and accuracy, you can have something accurate with poor precision, and vice versa.
(Unless I'm confused here, which is entirely possible.)