Ahhh! Now that I actually SEE the "All-Purpose Saw" I recognize it as similar to one I have. In another thread on this forum, I asked for a picture, and later came across this thread. Mine doesn't SAY "All-Purpose Saw", nor does it say "Thor" as the brand, but only as the parent company. This suggests that it was sold under both brand names, which may help narrow down the date. Mine is painted with a "hammertone" finish, not polished, and the foot is far lighter in color, but I think we're looking at the same housing structure. What differences do you see?
I'll have to locate mine, and look at it from the same directions as your photos, to make a better comparison.