Yes, you can remove it extremely easily. It's held on with an Allen head screw. As for filling the hole, I've never bothered on my sabers but I would guess that it's 8-32 thread like most of the other US fasteners. If you want the cleanest look, a short set screw could be screwed in flush with the surface. Personally I don't even notice the leftover holes and they don't strictly need to be covered, but it should be easily accomplished if you wish. Good luck!
Great! I kind of knew I could remove it pretty easily but it was more what to fill it with that concerned me. Sounds like you don’t have to actually fill it with anything if you don’t care to. Excellent! Thanks!