I've recently acquired a couple of RB67 Pro-S bodies along with a bunch of lenses and other accessories, in the hope of rationalizing my kit, and selling off the duplicates and un-needed bits. There is one wrinkle with the set - there are three rotating back adapters for the two bodies. I've done a bit of experimenting and determined that: 1) The 3rd rotating back adapter is actually a Pro (not a Pro-S) adapter. It works fine on the two bodies, but I don't get the benefit of the enhanced interlocks or indication of rotation in the viewfinder; 2) One of the two Pro-S adapters works fine on both bodies; and 3) The other Pro-S adapter includes the correct indication of rotation in the viewfinder, but something about the interlocks isn't correct, because it won't let me release the shutter on either body. Here are my questions: a) any hints on what I can check on the adapter to see about correcting the problem; b) if I have to get another adapter, can I use a Pro-SD adapter with my Pro-S backs and retain full Pro-S functionality?; c) how do you identify which version of the rotating adapter you have?; d) anyone have an extra rotating adapter on hand? . If necessary I see that KEH has them listed for sale. Thx in advance.