Hello Rick
we meet here as well I see !! welcome to my other obsession,
this is a photo of my C15A 12 cab, as others have indicated you should have the 2B1 steel drop sided body, full transverse tool box without any spare wheel carrier, the 11 and 12 cabs were fitted with run flat tyres so never carried a spare.
If you go here
http://www.canadianregister.co.uk/ you can see how many C15A 12 cabs are registered world wide, there are known to be a few more but these are in the main un-restored and not too many of these either.
The OCMP have two on charge, mine and a tanker of Steve Stones currently under restoration.
The role of the truck as a 15cwt 4x4 was varied and in both the Canadian and British army it was used as officer transport in the field before the jeep replaced this type of vehicle, it was used as a section truck, as a run about for front line infantry sections and armoured regiments and also as a towing tractor for the 6pdr anti tank gun before this gun became obsolete.
Many 11 and 12 cabs went direct to the middle east and either perished there or subsequently in Sicily or Italy and never returned to the UK. Those that survive today are almost certainly base vehicles that got left behind during the second front when all front line units were re-equipped with the latest 13 cab stocks.
Having said that there is photographic evidence of 12 cabs in Europe. I have a reference that’s states that the Polish and Cheque free forces were equipped with them, it is unlikely that these would have ever returned to the UK.
Amazing find good luck to your friend it is certainly worth saving.
Pete