Nothing in the side frames, I am sure there is probably some sort of seal between the upper and lower windows. Can't see it though.
I have looked for a Brand name, but haven't found anything on these windows.
You have to really yank on them to get them up. My wife can't open them.
Won't try again until warmer weather.
The window over the sink is a crank out and has a sticker that says "Rail-Lite Division", and some numbers. I double checked and it doesn't say Trail-Lite, which is the brand of the trailer. Thanks everyone.