George, I'm not sure about interchangeability but this part seems to have multiple numbers including 112 260 05 20 in the 1964 edition B parts list and 111 260 13 20 in the 1967 edition C. There's also at least one W110 part, 110 262 04 01, that looks identical. I don't know why the part numbers would change unless there was some dimensional or specification difference, but they certainly all look the same. The gear ratio and cut should always be the same, right? Do you have a set of digital calipers to compare dimensions?