Fuse block fasteners
Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models
The original fasteners that secured the fuse block to the headlight bucket are 4 mm × 0.7 mm × 16 mm. Were I to need replacements, I would likely select McMaster-Carr part number 91200A136. I would combine this screw with a fender washer, McMaster-Carr part number 91116a130.
Charlie Mullendore of Antietam Classic Cycle provided me with some additional details. In Charlie's own words:
4 mm × 0.7 mm × 14 mm round-head slotted, with a split lock and 11 mm OD flat washer on each.