I just picked up an ABC razor at an antique store. Pictures pending. MY question is there are 2 serial numbers stamped onto it. One is an "A" which makes sense. I don't have it in front of me but I believe it is a 1907 model. The other code is stamped on the same face, but on the other side, so it is upside down. Just spin it around 180 degrees to read it. It has an "L" in front of the number. What is that second number for?