BCP could be the USA's "Building Partner Capacity" policy which supplied information and equipment to 'Partner' Governments and has done so from 1940 till today.
These Chassis would, or could have been training chassis to train Military & Civilian Mechanics how to assemble and repair different vehicles. The War Department Chassis may have been of Ford Produced Armoured Cars and other specialist chassis. The convertible chassis could be training aids showing how to convert an existing chassis into another type, for example, a standard Ford Chassis into a Marmon-Herrington 4 or 6 wheel drive.
Just my 2 cents worth.
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Cheers
Cliff Hutchings
aka MrRoo S.I.R.
"and on the 8th day he made trucks so that man, made on the 7th day, had shelter when woman threw him out for the night"
MrRoo says "TRUCKS ROOLE"
