Those steel soft plugs are prone to rusting. They aren't too hard to remove if you can access them. If they're rusty enough you can drive a screwdriver throught them and pry them out. If they're solid, get a big sheet metal screw and run it in, then pry on the head. The hard one is between the bell housing and the block. I have started replacing them with brass, your parts store should be able to sell you the right ones if you know the diameter and style. They're either a cup or dish style.
