Barry, thanks for the info on how the seats were mounted in the C15Ta. Im not sure this is how the Wire-3 had them though. When I tried out my seats in the box the other night, they seemed to match up to the wheel well height pretty closely while mounted on the original seat sliders. I have been told the seat mounts appeared similar to the 8cwt wireless truck seat mounts.
Chris, your point about the tray under the table possibly being for another wireless set is very good. The table tops have a variety of different mounting holes and I believe it was intended that this truck could carry the WS9, WS11 and WS19 radios.
I tried out the two cable reels I have and they both fit perfectly on the threaded rod. The rod is 1/2" diameter carriage bolt. Im not sure if this was added by the end user or came from the factory. You can see that the smaller diameter reel does slid around on the rod. If this was in fact what it was for, Im wondering if a compression spring was on the rod between the mounting bar and the square plate. This would keep it away from hitting the bar.