Yes on closer look you do have a seat from a Ford. It was called the rest-o-ride seat. Like I had said I have seen this done before to other super 55s. For your 1955 super 55 you should have what I call the leaf spring style seat. Not the rubber torsion style. If you look in your parts book you can clearly see what should be on that tractor for that model year.  Hope this helps you out!!