I did a lookup and TRD makes one for the FRS. Theirs I believe is plastic and uses templates to position straps with nuts to the window using double sided tape. The louvres are then placed on the window and secured using a flush mount socket head screw offering the ability to remove them to clean window.
Here is the install and review of their option, just seems better thought out.
http://www.ft86club.com/forums/showthread.php?t=69293