Hello psmith,
Welcome to the Stovebolt site. All of the US made trucks made pretty much from the beginning of time up to the automatic choke era have both a hand and foot throttle. The hand throttle is primarily used in initial start up of the engine much like the fast idle cam on later model carburetors. The hand throttle was also used to add RPM for winching, dumping, creeping along in farm fields, or other tasks requiring a little more engine speed. I have never seen a throttle on the steering column. A picture would be great. Hopefully someone with greater knowledge of 1930's vintage Holden's can shed some light on this.
Paul
