Based on your desctiption of the machine, I'm going to say it's a 7 digit number. The six digit one in the G9 range is a 66 which is full size machine. The seven digit indicates a 128 born in February of 1923. The 128s are 3/4 size machines usually found in bentwood cases. Mine is a cutie. Be prepared to fall forward when you go to pick her up. That little darling weighs 29 pounds. Do not use the handle on the case - the handle is strong, but the hinges will need looking over. I often say that if Miss Mamie gets tired of being a sewing machine, she can have a second career as a boat anchor.