[Arran]

If the chassis has a brass data plate riveted to the rear apron, or the tube shield on the 1931 models, then it's either an export set, or a Toronto made Philco. The U.S sets seem to have used paper labels on the chassis, with the exception of the 1928-29 models, maybe some of the 1930 sets as well. In any event I have run into variations in Canadian built Philco cabinets as well, I think one of mine was built by Thomas (or some other firm) in Woodstock, Ontario, another I saw was built by McLagan in Oshawa. Woodstock is near London, which was the H.Q of Sparton of Canada Ltd., so Thomas built a lot of Sparton cabinets, they are still in business making school busses. Philco Products Ltd. of Canada may have made their own cabinets as well, but I haven't been able to confirm or deny it, given what most manufacturers did at the time I would guess not. 
Regards
Arran