Does your roof have a dome like shape to it looking at the roofline from the back of the trailer? If so, it's a magnum roof.
2015 Jayco 24FBS Elite Jay Flight
2013 Chevrolet Silverado 2500HD 4X4 6.0L 3.73 Axle
HD Trailering Package with Integrated Brake Controller
Equal-i-zer Hitch 10k/1000