I have never seen the likes of that. I have actually been slightly involved with AC design and window AC's always have the "fins" on either side. Perhaps the logic might be that on a hot rainy day, the water might provide some considerable additional cooling to the outside condenser. Evaporation of water on the hot coil will help a LOT with cooling efficiency.
Another CONCEIVABLE reason might be that some people object to the tap, tap of rain on an air conditioner...the louvers might help break that up.
And a third that I actually like. Occasional rain might help CLEAN the condenser coils...but then it might also help corrode them. And then there's the thought of rain onto an electrical compressor...scary.
Well, live and learn.
(Mine are through the wall with both input and outflow on the back. Not the most efficient but that's all you can do with a sleeve. but it's UNDER the windows rather than through them, a BIG plus.)
See if you can find some white duct tape and cover the top louvres until you are certain it's safe.
Last edited by zip2play; 06-24-2013 at 08:44 AM..