Thank you, footgoose. I'm the third owner of this bike, it's mine since november 2018 (with only 6 500 km on the odometer).
Since I bought it, I've driven 4 000 km : simply, the best bike I ever had !
The back line of the bike matters to me, too . That's why I was looking for this Guzzi accessory.
Thank you docc. About the "clamps", I understood well what they were used for, ............but I didn't have the right tool to put them on, at the moment I took the photos !