Did all 72 Blazers have dual horns?

[Toro]

Mine currently doesn't even have one. I need to have one in order to register it. I searched a few of the threads and found conflicting reports of what was standard and optional. Most of those threads were for trucks, so just wondering what would have been on a 72 Blazer. I saw some SPIDs with dual horn option on earlier year models, but don't think that was the case in 72??? Thanks if anyone can shed some light on this.