Rear hub has slotting in the flanges, a-la Record/NR/SR. Front is either an early, early G.S., or it might be badged Fratelli Brivio, who has been credited with producing them for Campagnolo. For that matter, they have been attributed the other way 'round too. What came first, the chicken or the egg?

For the record, Exhibit A: A pair of Fratelli Brivio track hubs (yes, they are mine, no, not for sale). Marked with the Fratelli Brivio logo at the center, "F. B." around the perimeter of the dust cap seat:



-Kurt