Sometimes, when copies are made using an actual skillet as the pattern, the markings are removed by scraping them from the sand on the inside of the mold cavity. This has the effect of enlarging the cavity, meaning more iron is needed to fill it, thus the copy is unduly heavy. Yours is probably an older smooth bottom unmarked Wagner, which may have pre-dated having "10 INCH SKILLET" or the like incised on it.