If you want to check out the bottom side of the roofing material try removing a ceiling roof vent trim plate.......that usually exposes the folded over piece of roof material so you can see both sides. Refer to the Dicor video attached.
In the "early" days TPO came with smooth and fuzzy underside finishes. My 2013 ACE has the fuzzy underside TPO which is compatible with the basic Dicor roof caulking, but I think the newer TPO (smooth underside) requires the special Dicor cleaner and a different Dicor caulking......could be wrong, but I think one of the other Dicor videos or info brochures on the net somewhere, refers to that aspect.
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