Hard call on this one. The markings are of the earliest style and the pan has the scooped handle like early Griswold skillets and even many later Wagner skillets but the casting quality is suspect.
What is that "line" on the bottom off center? Shift in the sand mold? Gate? Is this a copy casting? Is the pan ground on the inside as Wagner would have done? I can't tell if the pan is an original or copy. And, from the photos I can't really see the typical reinforced top rim or handle attachment as used on the earliest Wagner and Griswold skillets. Looks like this pan is related to early Griswold skillets as are many of the Favorite 12 skillets. Again, I don't know if these are copies from a Griswold skillet, made from a modified Griswold pattern, the same pattern maker made patterns for all three companies, or what. But I don't think I have seen the really early Wagner No.12 skillets either. Large castings are harder to make than smaller ones so that could account for the less than great casting.
Steve