To answer your question: No one is impounding RV's because they are overweight. As a recreational user, you don't have to go thru weigh stations and short of really bad gross negligence they will have no idea if you are over weight.
But looking at your post, I'm pretty sure you have your numbers mixed up.
- GVWR: The maximum weight of the individual unit (truck and trailer each have separate numbers)
- CGVWR: The maximum weight of truck and trailer combined.
There are a handful of other ratings that come into play also.
I can't say with certainty without the full details of your truck but most likely it would be fine and within the limits.