For reference sake when searching, these are called jalousie windows.
Not the best for keeping the weather out, but certainly worked in years gone past.
If you can find a local RV salvage yard, they may have something that fits.
Might be a good time to put a more modern slider style in.
2007 GMC 3500 dually ext. cab 4X4 LBZ Dmax/Allison - 2007 Pacific Coachworks Tango 306RLSS
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