Hello, I am new to this forum so I have lots of questions. Here it goes. I bought this Grafmatic 23 years ago. Never had much use for it till i decided to buy a Graflex SLR series b 2x3. Looking at several examples. mine seems different, sort of. It has the channeled groove on top and bottom and down the front but it has two ridges like a graflok I think. Anyone know which this is. I am hoping it will work on a series B as I can't find a roll holder for it. Attached is a pic of it. Thanks