Posted By: 
Mark SteinbergDavid... that's a great catch.  
Donald Frangiapani had a similar coding system which he would write on the back of autograph cuts, pictures, etc.  He would even write his "code" directly onto autographed baseballs (right by the stitches).  
I never understood who would want this, as it really marred/tainted the piece to have this in plain view (aside from the fact that these fakes were already tainted...)
I bet the CM does indeed stand for Christopher Morales.  He "authenticates" most of the Coach's Corner stuff, and this one has all the earmarks of one of a typical C.C. offering.  
Thankfully, I have never possessed anything from this authenticator so I don't know if his codes begin with CM.  It would certainly seem to be a logical assumption and explanation.