The characteristics of what have come to be dubbed SMS: Southern Mystery Skillets are inset heat ring, small pour spouts, raised size number and molder's marks, plus a handle reinforcement pad. This pan would not be considered one of those.
Thanks for the clarification of SMS. It definitely isn't that, but still a mystery. Does the #9 on the bottom and the under side of the handle give any clues to a manufacturer? I doubt it, but just asking.