There were 3 variations of the Sweetheart logo -- 1920, 1921-22, and 1923-35. Your logo looks like one of the earlier ones, but I cannot tell which one because of the rust.
It is fairly common to find construction materials that differs from what is listed in the Stanley catalogs, particularly during the war time models, as mentioned above.
I find the Stanley level models and construction particularly confusing. I am not sure all the Walter info on them is accurate.