We have a 2021 Highland Ridge - Open Range stick and tin (conventional) trailer. It has a 3/8” walkable roof deck, although ours did not come with a ladder. I noticed the other day from my stepladde...
After just doing a roof they use a cloth tape on the joints of OSB to keep it from wearing a spot through the roof, same with the sides of a trailer where the roof joins.
After looking at it doesn't look wide enough for the cloth tape.