I havent seen much love for the 2016 California special aftermarket or Ford parts. But, I did just find this:
A little pricey for my tastes, but nice to see some 2016 GT/CS parts...
New. Opened one side of the package and decided to go a different route.
$80 plus shipping
Links to product pages:
http://jaegerbrothersauto.com/auto-parts/2015-2016%20Mustang%20Splash%20Guards,%20Full%20Set_637.html
http://www.americanmuscle.com/splashguard-set-2015.html