Hello! I am a new cast iron nerd and need help with identifying a frying pan I am currently restoring that was purchased at a garage sale. The only markings are on the bottom of the pan near the handle. It says, "12 7/16" and "10" and in between there is what appears to be a Phillips head screw head. Obviously the 12 7/16 is the diameter (thankfully it's not 12 1/2 because that would be too big ) Any ideas as to the brand and age? Thanks!