The seller says they are not lathe lines. Anyone want to tell me why they are not lathe lines? My ignorance far exceeds my knowledge, but I would by it quick if someone told me that is what they were.
Simple, lathe lines appear in the fields not on the devices. Basically, the blank die get machined down to spec using a lathe. If the modified blank die does not get the proper polishing, these lathe lines end up after the die is pressed into the hub. Of course, since the devices are the deepest portion of the new die, evidence of the lathe lines gets pressed out. When the lines appear on the devices, its usually from some type of polishing brush used either to remove debris build up or simply to rough up the device surfaces for some other operation.
If the reduction of the master to the master hub is rushed there can also be lines left from the cutting bit on the devices. Unusual but possible. Also lines might remain on the devices if the shaping of the die blank by the lathe was coarsely done. In that case lines would left in the fields as well, but the fields are then polished removing the lines there.
Any remnants of lathe lines originating with the master hub and transferred down through the die production process to the working die would not deviate from working die to working die.