Yep, I've got a copy of report 141 which shows Canadian establishment of 348 T16s with 266 being on hand and a deficiency of 82.
Not trying to discount anything but also didn't want to jump to conclusions either. I'm down here digging for proof and answers with everyone else
One issue the report covers is the role of 4.2" mortar carrier and that 100 were so modified for use by the end of April 1944. Plenty of time to load them onto transport from England to France if the modifications were done in England but no time to get into action on D-Day if the modifications were done in Canada. Same report mentions problems and solutions being worked out in a memorandum dated 4 MAY 1945 and this would be a good document to try and locate since it might indicate reports of field trials occuring prior to that.
Maybe we can get Clive to make sure the Carrier WoW has a big section on Canadian T16s before it is released. These books have lots of details and I'm sure there is sufficient market with all the variations.