These salt and pepper shakers can be found in Larry Carey and Sylvia Tompkins first reference book in 1994 on page 40 about Black Americana shakers. At that time they were noted to be incised "877 USA" on the bottom, but the maker was unknown.
The middle photo above is from a portion of a Camark Pottery catalog. The company is an Arkansas ceramic company. According to Camark Pottery reference books, they did not make many S&P shakers. This set is mold number 877. So far, it has been discovered in five different colors. Circa 1940s-60s.
