Mine is about the same, rack is about 20lbs, spare 60-80lbs, ammo can-35lbs, and I use mine to pull up on all the time.
My father works in the RV industry and they build hitch couplers, generally the rated weight is half the actual working weight. That is to avoid lawsuits and to give plenty of cushion for flaws and user error. I would say a 200lb kayak would be just fine, just check your bolts every once in awhile...