Not trying to be funny, but nothing functionally. The normal model has just not been tested/certified for the CA Approved Roster just yet. It could be something as simple as drop test, loaded chamber indicator, micro stamping requirements or even a change to the pistol which would require it to be certified/re-certified. Cali makes it tough for ya'll man.

The 70 series 1911's (no firing pin block) need to pass the drop test and may have a heavier firing pin return spring and/or a titanium firing pin (lighter and less inertia than steel) to do so.