I have a Stanley No78 Filister & Rebate Plane that belonged to my Father. I am considering selling it but am reluctant to do so until I have found out a little more about an ENGRAVED/CAST signature that appears on the working face of the tool. It begins with what I think may be a capital 'E' and then possibly an 'm' .... the rest I'm finding it difficult to decipher. I have a suspicion this might be a cast signature to designate this plane as a Special Edition model. Would I be correct in my assumption?