Street view was recently updated, here is the siren back in 2011:

Street view updated in 2013, now the siren is gone. All that remains is a cement slab and rusty bolts where the siren pole was once mounted.

I looked around some more and I found that as of August 2013, an MD on West Sunnydale Lane near Norway Drive is the only one left. And it seems to have a newer radio antenna.