I have a 2006 Montana Mountaineer that has GVWR of 12275lbs but has 6lug 5200lb axles. This doesn't seem right to me but I guess they deduct some for pin weight. It came with Load E tires but I've had...
12,275-20% pin weight is 9,820, so your axles and tires aren’t underrated. You may want to weigh your trailer though. It’s easy for them to gain weight over time through mods and repairs. Overloading them is easy, especially with full tanks.