I can't talk to the actual construction, with that said if the Mfg says it is a walk on roof does the construction make any difference something that should be considered the the weight of the person doing the walking. A really heavy person might want to cut (4) some 1/2 ply into strips about 8 x 36 or so and place these on the roof to walk on to spread out the weight.
Jake my sidekick (yellow Lab) 10/04 - 05/20
2017 RAM 2500 CC 4X4 Cummins Diesel
2016 Flagstaff 26 FKWS
AF&AM & El Korah Shrine of Idaho