I can see it being ok, on the basis that the S fairing was available for optional purchase when the bike was new. Covering one's ass by documenting and sending in pics to their office is a good thing to do though. I've got the factory optional futura fairing for my Laverda. I have chosen for the time being to run it without the fairing. I sent pics in of the bike with and without the fairing, and a letter explaining my intention to ride the bike with and without the fairing based on season, and my whim. They are ok with that.