M6 Bomb Service Truck information.

[Charlie Down]

Thank you Terry, Bruce and Colin.
Agreed to all the above comments that I may be clutching at straws.
However there is no known other alternative at this time.
The 1533X2 was built in late 1941 and the M6 went into production a year later, so the 1533X2 riser was most likely adopted as a basic design for the M6. It may have been that the War Department wanted a simpler spare part chain and asked for the 2 x CMP seat option, or something similar, or GM/Chevrolet foresaw the possible need and devloped the riser after production of the 1533X2 started, so initial production trucks had benchs. It could be all sorts of reasons.
The same fuel tank/frame/bench seat was used throughout the war in production of the American GM G506 series of 1-1/2 trucks, so it wasn't that they ran out of bench seats. I think it likely that GM Canada products were shared on GM USA products, why make new designs when a design and machinery already exists.
That doesn't answer why there were 2 different sizes/patterns of M6 Riser panels though. And if there was a reason is it relevant to the 1533X2?
As Colin Alford states production from bench to CMP seats took place in 1941 for the 1543 trucks and most likely for the 1542 and 1533 trucks. So it could simply be production lines adopting more 'Military' fixtures on their MCP trucks as time/planning went on, or new parts became available.
Frustrating as this is creating lots of questions, but as yet no answers!
Looking forward to the photos Colin, however I may not answer for a while as its already gone 1.00 in the morning. I know thats a bit slack of me!

Still don't know what riser panel it was though!