Tiriaq's description covers it perfectly.
In regard to finish, the Canadian stens were either a dark blue finish (very early), or a flat black. Post war, many Canadian stens were parkerized, along with British stens which were in Canadian service. These are the grey finish that so many people swear is the proper finish for a LB sten. There is a letter and two numbers stamped on the parkerized stens, usually on the mag housing, but occasionally on the trigger housing, which could be either inspector's numbers, or batch numbers during the refinishing process. I only find these numbers on the parkerised stens, be it British or Canadian made (but all out of Cdn service). Some of them even still have the origional finish on areas like under the mag release plate, which indicates that they weren't even fully dissassembled prior to parkerising.
Overall, the Canadian stens were a better finish, and the welds neater. Canada never went to either seamed tubing, or with the rolled and welded method, by what I have observed. The early rolled and welded stens were withdrawn from British service during the war, as the tubes were weak in the area of the trigger assembly, where insufficent material existed. I have seen a few of these complete canadian service, and all had buckling of the tube in that area. I guess the order to destroy them never made it to the canadian armourers.
Some of the rolled tubes had reinforcing plates spot welded to the sides of the trigger assembly. They also had an extra reinforcing plate added in between the plates forward of the sear. These did not have the weakness as the non-reinforced stens, and were not part of the recall.
Canadian stens were certainly finished more consistently. I have seen British stens blued, black, or parkerised, some of these were painted over, and some of them were simply paint over no real finish. But the variety of finishes on the British ones can be attributed to the number of different asssemble plants involved, and the pressures upon them to keep up production. Canada's single producer did not have to worry about air raids, raw material shortages, or losses of stores due to sinkings during shipping.