Not sure what factory channels look like but I installed the weatherguard mounting channels( see weatherguard picture,similar to yours?) and weatherguard 218-3-03 racks.Very industrial looking but will haul ladders or sheet goods.
Racks were PAINFULLY noisey until I filled the underside with expanding foam.
http://www.weatherguard.com/en/view/Products/Van Storage Equipment/Roof Racks/Mounting Kit/2085-0-01
https://americanladders.com/product/model-218-3-all-purpose-rack-aluminum-2-cross-member/