As NC Hauler said, speak to your RV manufacturer before using it. If you can get it in writing, that would be the best but even that may not help. Even in writing, it is only as good as the length of the 5er warranty. Even if Lippert approved it doesn't mean your RV builder would.
Call me anything you want but I would never use a GN hitch on a 5er. I have seen a few in campgrounds and the RV appears to be O.K. I have also seen a few with gaps between the cap and side walls. One campground I was in had a beautiful Heartland Landmark with gaps between the cap and walls that you could stick your fingers in to.
