I have 4 featherweight tables and all of them are wood tops, with cut out and steel legs. They have serial # on them.
Singer did make lots of furniture years ago and it may have been one of their regular care tables. It don't look like the extension table as it is wood top and only 2 steel legs. I also have one that is a reproduction that looks just like the others except it's painted black with a clear wood top.
If you only have the base of the treadle, I would put a glass top on it. If you are wanting to use it for the sewing machine, you can put a nice piece of wood on it and then have it cut out to match the machine. Cabinet shops have ways of holding the machine in place.