The more I thought about the buttonholer...it was purchased in 1945 and by that time this 1911 machine was old news compared to the newer electric models - so I wonder if this was a purchase made special to fit the owner's "old machine". The smaller modern buttonholers of that time would have been available by that time wouldn't they? I have one dated 1947 by Singer for my featherweight. I bet they bought this big honker to fit this "old" machine in particular.
I will take a picture and post later on - the Husband is off today so we are in and out of the house running errands.