M6 Bomb Service Truck information.

[Charlie Down]

I am researching details for the Chevrolet 1533X2 Long Range Desert Group truck. The particular area I'm trying to nail down is the riser panel on top of the fuel tank that allowed 2 CMP seats to be fitted instead of a bench seat. The only other Chevrolet truck I know off that had 2 seats on the fuel tank is the M6 Bomb Service truck.
I'm trying to get photos and dimensions of the M6 riser panels, of which there seems to be 2 types, one with raised rings pressed into it and the other with 'C's pressed in. Also the 'C' type seems to be much larger than the ring type. I can't find out why there are 2 different riser panels of different sizes, and therefore its not clear which one is appropriate for a Chevy 1533X2 truck built in 1941 in Canada.
The other information is from TM 9-765 parts catague which lists the following drawings, part numbers and figures which I would love to see.
M6 Panel cover, seat riser. Drawing and part number CV-471037 and fig 18-9.
Also M6 platform, with seat riser, assembly, drawing and part number CV-3666270 and fig 18-2.
These might help explain how it goes together or why there are 2 sizes/pattern, but maybe not!
I've attached some of my early research pages on the seating, factory photos showing the side view of the fuel tank frame and riser panel, and a LRDG truck showing a bit of detail of the side and rear of the fuel tank frame and riser.
Any help would be brilliant, I've been trying to work this all out for literally years and its the final detail I need.