Font Substitution?

Strange font for California 128 marker in Geyserville

As Geyserville Avenue approaches its intersection with California 128 in Geyserville, this marker makes an appearance. The font that's used appears to be almost, but not quite, Helvetica. Even the CALIFORNIA text banner uses the different font. Normally, fonts from the FWHA Series set of fonts would be used.

This photo was taken in downtown Geyserville in August 2009.