These latest editions have the same bottom plates and similar top plates (both are plastic). These plates are obviously different from those on the earlier editions of K1000 and K1000 SE. In addition, the battery covers on these latest editions are made of plastic and not compatible with earlier editions.
The new plastic top plate reduced the numbers of parts in the assembly.
Why to get these latest bodies? They are of less weight, but more importantly, the light meters in them are likely to work due to the newer electric parts.