Here are some part numbers I found. Hope it helps:
the 10 triangular "butterfly" washers, the 2 brass plano-concave washers, the one steel cone washer, and the two acorn nuts. They are indeed getting hard to find new. There used to be a package containing all the necessary washers and a pair of acorn nuts, p/n 3744 826, but it's NS1 (no longer available). The triangular washers show as still available individually under p/n 3751 636, the plano-concave washers under p/n 3751 637, and the central cone washer p/n 2121 223 has been superseded to 5301 0091. The acorn nuts are NS1.