Andre I wouldn't let steel wool anywhere near my trains! Especially not the 2055 / 2065 which have magnets in their chassis for traction. If the side rods are rusty, that's realism! If it bothers you, you could use nylon Scotchbrite or a chemical solution that "dissolves" rust.
Yes the Kusan molds were reused by K-Line. However the K-Line versions ride a little high, because each truck contains a huge, transversely mounted can motor geared to the wheels. Unless you permanently rewire those traction motors in series, the K-Line diesels run REALLY fast! I bought a set of the K-Line FAs wasn't happy, and promptly returned them. YMMV.