There are many differences. For example, the rubberized curtain on the K1000 is enhanced. Whether or not it has PRECISELY the same length aprons, I do not know. I think that direct interchangeability is going to be tough here. Even Spotmatics differ somewhat from different versions and dates of manufacture. The earliest had circular screw rings (under film advance lever in order to remove top) that unscrewed the opposite way from the latter versions. When a model is as successful as these two were, there are manufacturing refinements DURING the manufacturing process. I have taken apart both in order to do minor repairs like cleaning the prism area. There ARE differences, septim. - David Lyga