I recall that they made this virtually identical stove for two years, 56-57, with some automatic burner differences but cosmetically the same. So I think Sandy is right that the manufacturers went to the clean ('sheer' in the case of Frigidaire) look in 57, I think this was a hold over for Westinghouse. And I don't see them often, they may not have sold well because they would have looked dated next to the new look from other models.