On my '46 I have the Key, Choke, Throttle, and Cigarette lighter right above the ash tray.
Directly below the ashtray, I have some sort of cross brace/support attached to the dash with two "acorn nuts".. just to the left of that is the lever that opens the vent right in front of the windsheild.
I assume yours is a canadian truck, so who knows if they were set up different than US trucks.. but my first guess would be heater controls.
Even in U.S. trucks, there dosen't seem to be a "standard" spot for heater controls to be mounted.
In my '46 the control switches for the heater are under the dash below the headlight switch.. in both the '50 trucks I have, the heater controls are located at the bottom of the dash in the area below the ashtray.
