CR FOLK:
The Zeus 102 catalog (printed in 1972) shows that they were already producing Zeus-2000 centerpull brakes with recessed allen fittings. (By the way: inside the 102 catalog is a picture of people looking at an earlier Zeus catalog which has a silver cover; anybody have one of those?)
The Zeus SUPERSER that Ocana rode in the '75 tour had recessed fittings, but he was competing with Gimondi who had brazed-in brake bolts. They were both sporting that sleek 'nutless' look.
The 2001 sidepulls circa 1976 were available both recessed and nutted.
On the other side of the pond, my 1981 Trek (the one with Columbus tubes, Cinelli bracket, and vertical dropouts) has recessed nuts.
Brad Stockwell
(first experienced "recess" in 1964 at
Aquidneck School, Middletown, RI)
Palo Alto