By far, the majority of Martins sold in the last twenty years have bolt on necks. All of the ‘affordable’ Martins are bolt-one. When you look inside at the heel area and see a small piece of wood glued to the heel block, you are looking at the cover for the bolt. A real Marin has a heel block with the company logo, model and serial number burned into the black...not on a piece of wood covering a bolt. There are other perhaps more serious differences.