If you have the integrated fan/vent/light/skylight fixtures, yes, they did come with some type of plastic on top of the vents. If your trailer has the rear bedroom, as it appears in your gallery, I can imagine why the back fan's skylight got blocked off.
I think I'm going to replace mine with aluminum covers because the skylights let the inside covers get pretty darn warm about noon time.
1975 Argosy 28 "Argosy"
1979 Excella 500 31 "Betsy"
1992 Lincoln Mk 7 LSC
2003 Dodge 2500 Cummins "TowHog"
"Lucy Loosehair" the cat - Airstream mascot
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