Brake light switch set screws (rear)
Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models
Thanks to Bruce Giller and Csaba Descardes for sharing this information on the old Yahoo! Loopframe_Guzzi news group (which has now moved to Groups.io).
The size of the set screws for the rear brake light switch is 3 mm × 0.5 mm × 10 mm long.