More commonly called "Cover Boards"....
TSC used to have add-ons that worked just fine....some after-market cover boards are steel, some plastic....I guess both work well....at least I never broke a plastic one....!!!
One of the most improtant parts of the AC plow is the Heel ...or Heel Slide..it must not be worn out....doesent cost much to replace...Bolts to the rear Landslide.... The Hydrolic hose bracket on my Semi-mounted has 2 spots for hoses....never used the second ....only uses 1 hose..!! The rear wheel "Scizzers" should be in fairly good shape ( or rebuilt ), or it may "shimmey" at highway speeds...