Has anyone ever seen this?

[Greg Maniero]

I recently purchased a used bass that leaves me with some questions. I fell in love with the sound but am curious about its origins. It was appraised as a c1939 Andreas Wilfer but looking around I have found no reference to an Andreas Wilfer that is that old. I tried to email the Andreas Wilfer company in Germany but it didn't work. The person that I bought this bass from bought it in Toronto from a private seller. My question is about a CM that is carved into the neck heel. Has anyone seen anything like this. I thought that it may be from a school but haven't found anything that matches. I tried the Royal Conservatory or Music and the Canadian School for Music and Dance, contacted a bunch of Canadian lutiers, and inquired on other online sources. I thought that I would try the expertise found here. Thanks for any help you can provide.