Seeing as the 9th is the most overturned Circuit in history, it wouldn't surprise me for the SCOTUS to overturn the ruling on the merit of the case. Can a local governemnt prohibit some forms of exhibition or sales on government property.
Now, it's just my humble opinion, but if the SCOTUS overturns the ruling on the merit of the case, and agrees or states the 'incorporation' portion is correct, then we can sit in awe of the judicial process that finally 'got it right'.