I bought one recently and it has a kayak rack on it, it goes thru the top with about 3 in (didnt measure) steel plates on top and bottom, and by condition of foam on kayak holders it has been on there for quite a while, there is no evidence of leakage, even after the hard rains we have had. It looks like they used a caulking type tape versus caulk around to seal, I will however caulk it quick around edges before winter for extra caution. The daughter does have kayaks, I am not sure I want to actually use the roof rack.
I am NOT a fan of attaching any racks to a Pup roof. It can be done but you have to be very careful about maintenance - diligent caulking maintenance for sure.
I built a pair of lift off aluminum racks that are supported by the trailer frame fore and aft the camper body to carry my canoe. I also built a spanner frame that carries 2 bikes upright next to the canoe when we want to bring them.