I've found out a few things:
1. Early 640 adventures with the high guard have a different lower casting arrangement so the early stock protectors won't fit the later bikes with bigger fork tube diameters.
2. The latest 990 lower castings have a different hole spacing for the fender (compared to the 640)-they are closer together--haven't checked the 950 versus the 640 yet.
3. I can't find any off road fork that has similar lower castings--so the 65 protector looks like the only one that's close (front two holes are parallel)--and I think this has already been discovered.
In conclusion it looks like a "special" protector is required if you want to fit a high guard--even cutting down the current low fender wouldn't work if its the 2 bolt only mounting system--too flexible.