The raised rim was added to "Great Seal" US Army buttons in 1910. In the World War One era, they had a "black finish" applied to the front so that the yellow-brass button would less less visible to the enemy in combat. The "black finish" was discontinued in 1923 (and never resumed).
I should mention, the "black finish" was thin, therefore, heavily-used buttons show the black has worn off of the high parts of the emblem and the rim. But the black tends to remain in the grooves of the horizontal-lined background around the emblem. Although your button is incompletely cleaned, no black is showing in the lined background, so it is probably a post-1923 one. You might want to clean it better, to make sure there is no "black finish" anywhere on it.