Haulmark trailers ok?

I have an old '97 10' X 20' Haulmark 7000lb. At 7k pound max you can only carry like 3500lbs. Not positive but trailer by itself is 3500lb.
I TOTALLY agree with the heavier axles. A B-body could fit in my trailer if I had to move one for someone, but I would worry about the over weight.