The way I read it the "Superior Quality" backmark was one used by Steele & Johnson. They were in business in one form or another from 1852 until 1920 when the Waterbury Button Company bought them. The firm was one of the four major 19th century uniform button making companies. I can't help with what uniform it would have been made for.
My information came from "American Military Button Makers and Dealers; Their Backmarks and Dates." by McGuinn and Bazelon. I found it on pages 154 and 123 in case someone more knowledgeable wants to add anything.