I got my blower from Ford a year and a half ago for my 98 GT, knowing that it had no CARB # for Calif application. Here is my best *guess* as to why it had no CRAB # - the fuel tank vapor purge system is diferent - different valving, different sensors. The result is that I always have a "check engine" light showing due to the missing fuel-tank-purge sensor(s).
Whether or not this is the case for your new Roush/SVO system, I can't say.
The "check engine" light does not seem to have any effect on performance, and it has very little, if any, effect on actual measured emmisions - my measured emmisions were a factor of 10 or so below that required by the smog check limits. But it may make your smog guy take note of the "check engine" light
Bottom line for me? - like stangin' said, the car passes emmision limts (as of 2 weeks ago) with flying colors, but will not pass visual inspection, both in terms of the CARB #'s, and the "check engine" light (at least in regard to my 98 GT with the Ford SVO kit). So, if you have a smog checker with whom you have a good relationship with, you may want to "suggest" that he ignore the check engine light, knowing that it will pass the actual emmisions test which is what gets modemed to Sacrametno by the smog-check machine.
Save the planet, dude. Do it for the children