I will take a minute to double check , but the easiest way to know what roof you have for sure , is to drop a vent bezel from the ceiling and look at the material that's visible ; usually a triangle shape , pushed down around the edges.
White on both sides is one type , white on top side and black on the other type .
Before I add which is which ( I don't trust memory any more ) I want to double check .
EDIT: Back in time to add the info here ; white both sides is TPO
www.rvhometown.com/tpo-vs-edpm-rv-roof/html