Our 1640 ESP came with the prorac rails installed from the factory. They are supposed to be rated for 150 lbs. But they are the entire width of the roof and the ends are supposedly anchored into the sides of the roof frame.
That Yakima rack you linked to says it includes 60" bars which would not span the entire width of your roof, would they? In other words, you would have to mount the tracks too far inward from the edges so the only thing supporting it would be the thin laminated roof. I wouldn't trust that to hold any weight.
I think this is the one that came mounted on my camper from the factory:
Permanent Mount Tent Trailer Rack | Bike Carrier | Water Sport Carrier | Cargo Carrier
Hope that helps!