Help in Identifying This Mark. (Raised KEYHOLE)

Hi everyone. I would appreciate help on identifying this raised logo if possible. The cast iron pan is approximately 6 1/2" wide. Double lipped. 3 notches. This has the appearance of a Lodge but the raised mark above the #3 looks like a "KEYHOLE". I have spent several hours looking for this mark both on U.S. and international websites but I have not been successful. Any help would be great.

Thanks,

Dave

It is a lodge pre 1960,

It is a Lodge. I've read that is a shift identifier marking. In this case, the "1" would identify first shift.

The 3 notches in the heating are essentially always a dead giveaway that it's a Lodge. Some Asian pieces will also have notches in the heat ring but the differences between and old Lodge and an Asian piece will be obvious.