I have emails from the city saying otherwise, I'll try and dig them up. I believe it's publicly maintained as it was resurfaced along with the rest of the town a couple years back when we lived there.

I also doubt the Wolfback Ridge Association paid for the bridge over highway 101 that's exclusive to them. There are radio towers (SFO?) up there but you can access along the fire roads from Tennessee Valley.

Edit:

Found it, response from Director of Public Works:

Not as simple a question as you might think… Short answer is that a portion of Wolfback Ridge Road is publically-maintained. For purposes of hiking, you and anyone else can probably access from the State of California right-of-way (at US 101) to the trails at the top of the pass anytime and not have an issue. Vehicular access is restricted at certain times of the year by Sausalito PD – Fleet Week and the Fourth of July based on lack of parking, lack of adequate circulation and inadequate turn-around. If you want more legal details, let me know – I’m researching the area for a development application anyway…it may take awhile though.

They have a point regarding events but if you park where he suggests you'll run into issues.