I refer to something I found on Wikipedia which may explain why the Canadian DuMont sets looked so good. Apparently Canadian sets were assembled by Canadian Avionics, manufacturers of flight simulation equipment, in Montreal. I recall the Fairchild name on some of the components and recall DuMont Fairchild on the rear cover. This may explain the quality difference between Canadian sets and US assembled Emerson sets.
The Canadian DuMont set was amongst the best constructed sets I recall of the period.
http://en.wikipedia.org/wiki/DuMont_Laboratories