There is a C/F mudguard on ebay, from a manufacturer in san diego. It looks good and who would know it isnt original!!!. But i have seen originals on ebay quite regularly,Or have you tried reboot guzzi spares they are/werebreaking a cafe sport so they may still have the mudguard.
Gary
Guzzi spares did not have any suitable mudguard and finally I ended up with an Aprilia aftermarket mudguard from Ilmberger. It's a bit short at the rear, otherwise it's quite nice.
/Ken