It depends on the 'freeboard' or distance between the top of the window and the top of the slide. I've installed awnings in a lot of strange places (I won't list any details
) but it should not be a problem.
If you have an trouble locating a matching awning, let me know as I am a dealer/installer for all of the major awning companies, including A & E.
Solar Tech Energy Systems, Inc.
Victron Solar Components and Inverters, Zamp Solar Panels, LiFeBlue and Battle Born Lithium Batteries, Lifeline AGM Batteries