Sorry, can't help. My 1988 Scamp
has glass in the sliding windows
and don't leak. We have archived threads for rebuilding Jalousies, but I don't remember any about the the sliders.
I have pulled the door window in my Scamp
(a couple of times) and there isn't any "rubber seals." The glass is caulked to the frame and there's "snap" gaskets around the edge. Those gaskets are more for asthetics than anything. You can find that stuff here: Interstate RV Metal & Supply
starting about halfway down the page.
Can you post some clear pictures?