Shroud Assy,Ref Fan SVCE (501R, 501F)
  501R    Part is NLA.
  501F    Prior to #M/P1004775 Except Between
          #M960170-M960319 And #M996400-M996574
          Part is NLA.
          Starting With #M/P1004775 And Between
          #M960170-M960319 And #M996400-M996574
          See 7019836.