OK, your pic is a little over exposed and I had to focus on the rear wall molding and then I think I know what you are referring too. It is hard in the bright sun to take pics of white things...
Is this what you are looking at?
Here is a slightly over exposed one too.
A side view
I can tell in your pic, that is the rear wall of the camper at the roof line. There is a piece of aluminum molding that has butyl sealing tape under it to cap off the back of the roof between the siding the top which is the rubber roof.
Under those mounds of Dicro caulk, they look like big quarter size dots about every 6 to 8 inches, are covering over the screw heads to prevent a leak and rust of the screws.
The rectangular openings I "think" you are pointing to is the way the molding of your vintage is made. They have a recessed section for the screws and the dots of caulk make it look like something was supposed to go in there but is does not.
See here on the front molding that joins the rubber roof to the front siding. This molding is made similar but it flat and no lip that goes down the back wall.
You can see the screw heads here before the caulk is put on. This is during a roof rebuild.
And here during the caulking. He has not made it to caulking the screw heads yet in this pic
Does this sound like what you are looking at?
Hope this helps
John
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Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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