To me it looks later Victorian era, 1870s -1880s. I use my wife's 4 sided foam fingernail buffer with multi-grit ranges to lightly rub down stamped and marked areas to reveal the marks to better read them. If you can read the maker you'l have a better chance at running down the pattern. You'l find those buffers in Walmart's cosmetic area. I just used one on and old shell casing back end to read the markings as they are not so harsh and destructive on old stuff with allot of aged patina.