I've taken apart a couple of Post-War East German 5cm F1.5 Sonnars in Contax mount, and just acquired one with SN 305xxxx. The rear triplet is held in the optical fixture with a retaining ring, and is not in a separate fixture like the pre-war lenses and wartime lenses. My latest SN wartime lens is 285xxxx. Unscrew the retaining ring of the main optical fixture and the "bare" glass comes out. It is more like the post-1963 (or so) J-3's. I also cleaned a couple of custom mounted post-war Sonnars, also in LTM. These looked like specialty work, and were stamped with the companies name.
I would like to see a thread showing pictures of and with your lens.
I would like to see a thread showing pictures of and with your lens.