I just purchased a 1948 Chevrolet Fleetmaster Woodie last week so I might have several more questions as I discover different items. The horn button was just sitting on the center of the steering wheel and came off. The horn ring works. Does the horn button normally work when pushed? Does anyone have a diagram of the horn assembly?

http://chevy.oldcarmanualproject.com/parts/1929_54/176.htm
That center cap is just a cover.

Congrats !!!!!!! Please show us pictures when you can . Thanks !!