I have at last identified my decantor.
It is Bischoff. It is shown in their 1962 catalog.
They were located less than two miles from Blenko in Huntington,Virgina, USA.
See catalog picture below.
Based on proportion, I think mine is the medium sized one.
The top rim looks skinny because someone has ground it down!
The bottom of the stopper has also been ground, in an attempt to
hide the chips caused by clumsy user inserting the stopper, and chipping the rim of the decanter. This poor repair is why the stopper no longer fits the decanter properly