Peter- a little info is in a recent thread of mine here-
You probably saw it already. Best as I can read the responses, there is no definitive answer yet. Some wonder if there was a change in the model III life. Someone wonders if it is only the GSW that has the newer patch.
Until I hear and/or see otherwise, I will simply assume that later GW patches will be like the one on my GW690, first version. i am rusty with rangefinders in general and take this camera out once week or so, so I haven't gotten completely at ease with the camera over-all. this includes the rangefinder spot. I still need to consciously find the spot and then remember which way to turn the lens, etc. this is partly because I am out of practice, and partly because the spot does seem smaller than what I have used before- primarily a Leica CL.
All in all, it's a quality camera. If you have used a Leica M3, then you might be constantly disappointed. As with any viewing system, people work well with different styles. For some people, a rangefinder will simply never work. For others, it is the best way to work. I would pay more attention to this aspect- does the rangefinder and its 'window' view work for you? Or are you a ground glass guy? The rangefinder on the GW690I is fine and I have used it in sunlight and interiors with equal comfort/discomfort.
I know that this isn't the info you wanted. I hope someone with the kind of experience both of us want to hear about shows up.