I'd agree with you, Mike, but where is the anvil?Saw set.
I've never seen one exactly like that. In the day there were hundreds of designs. I have at least a dozen and none have that circular extension. Most likely some type of anvil that could be turned to allow different offset angles for the teeth was inserted there..
Well I thunk it was an old dentistry tool....
So THAT'S what a left handed smokeshifter looks like!