Oneida Ltd. produced silverware from 1880 and are still in business today. WM Rogers stand for "William Rogers" which was a major silverware manufacture in the 19th century, during the late 19th century International Silver got the trademarks to produce the William Rogers brand. Oneida got the trademark to produce the Wm A. Rogers and 1881 Rogers companies in 1929 and started producing a somewhat lower-quality line of products using those companies’ marks til 1935. Since the spoon has "Onedia Ltd." on it, they started using that name after 1935. Your spoon dates sometime after 1935.
I have been collecting WM Rogers originals (not from international silver or Oneida) for a few years now..