Can you post a picture? With the standard FW card tables, it is hard to imagine using a treadle base, so I wonder if the card table is the one you're talking about.
There was an extension for one of the FW tables, so perhaps that is what you have. I believe it only came with 2 legs of its own, but someone could have taken it apart from the table (which had the cutout) and attached 2 more legs to it.
There was another FW cabinet with an oval top. If you have that one it is quite rare.