Sorting through my stash and came across a YHA209 left switchgear body that was a) made of plastic and b) had no hole for the horn, although you could see the outline for the switch hole and horn sticker on it. However, it had all of the wiring and switches for lights and indicators. The screws for the internal retaining plates were self tappers as opposed to tapped threads in the body. 

Does anyone know which model(s) this style might have been used on?

Thanks.