'49-'51 window gaskets...

[3streams]

I am preparing to restore the windows in a 1949 and 1950 Limited. The frames are in good shape but the gasket is shot from time. A few have the "U" shaped gasket and a few don't. Does any one know where this gasket can be purchased? It was carried by Vintage Trailer Supply but no longer I believe. I think these type windows were used on most trailers in '49-'51.
My second question is about the windows themselves. Were they originally single strength glass or plexiglass? All mine are plexiglass in both trailers.
Looking for any help or alternatives. I do want to keep the windows operable. Thanks.
Andy

[Frank's Trailer Works]

April can you post some photos of the gasket? I would switch to glass if it were my call. I personally would use regular glass, but some recommend safety glass or tempered.