Throughout the 1950s the Campagnolo Gran Sport had enjoyed a monopoly of the parallelogram design - thanks to various, slightly obscure, patents.
By the early 1960s these patents were expiring and the derailleur market was hotting up. Simplex, Huret and Gian Robert all had parallelogram designs in production, and many of these designs gave a more precise shift than the ageing Campagnolo Gran Sport.
Ever cautious, Tullio Campagnolo's response was the slighly underwhelming Campagnolo Record of 1963. It is basically a Campagnolo Gran Sport updated with an improved pulley cage with offset pulley wheels to give better chain wrap and a more constant chain gap. This long-overdue improvement merely allowed Campagnolo to catch up with, rather than surpass, its competitors. Campagnolo had even used offset pulley wheels on its lower end Campagnolo Sportman derailleur a few years before (in 1961).
The 1963 Campagnolo Record may not have been a technical tour-de-force, but it is nonetheless historic - as it is the first derailleur to bear the iconic 'Record' sub-brand. The two words 'Campagnolo Record' are unquestionably the most respected in the pantheon of great bicycle components.
I am aware of four possible variants of this iconic product:
The second version described in this list is the least well documented, hence my vagueness about its date.
This, well used, example of a Campagnolo Record is of the 'second variant' described above. It features:
It remains very unclear to me why Campagnolo chose to stamp the 'C in a diamond' logo on the flange that acts on the low gear stop screw. It is only a tiny logo, and it is on a part of the derailleur that is already prominently branded.