After you have removed the fasteners from the front fender, there are only two pinch bolts in the upper and lower triple clamps, and the fork comes out of the bike completely .
Personally I think it's easier to work on the forks while clamped into a vise with a couple of wood blocks, than to mess around with it still installed on the bike .
You might be able to dress out the rough spots on the fork tube, but if you get onto a rough section of road, you most likely will get full travel on the forks, and subject the questionable area to be in contact with the fork seals .
Only way to know for sure, is to try it and see what happens .
I installed gaiters on my R65, might not look great to some riders, but it sure beats paying for new fork tubes .
Not that it would make any difference, but the standard fork oil for the R65 is 7.5 wt., but that's not widely available outside of a BMW shop .
10 wt oil won't cause any issues, but I wouldn't go with any heavier weight oil .