The 'sheeting' is either TPO or EPDM material.
TPO is the same color on both sides where EPDM will be white on one side and black on the 'down' side.
To find out, simply remove a roof vent inside trim piece and some roofing material will be evident, peal it up and view.
2012 Fun Finder XT 276 Toy Hauler & Harley Davidson Ultra Classic with Condor wheel chock
2014 Dodge Ram 2500 AT 4X4 Crew Cab 6.4 L Hemi, 373 gears, tow package, Rambox option, Revolver X2 tonneau cover, Equal-I-zer anti-sway hitch.