My memory of this derailleur (although I have a similar memory about Zeus!) goes something like this:
Galli were stung into action when Campagnolo released the restyled Super Record in 1980. This suddenly made their existing offering look ‘rough’ and out of date.
Their response was this, very polished, design. I regret their move away from straight lines and logical adjustment screws, and see this ‘new’ design as a step backwards in everything put finish and logo. I do like the fact that you can take it apart, although, as is often the case, you have to love circlips.
This design did not appear until about 1984(?), just in time for Campagnolo to launch their radically redesigned C-Record groupset (and derailleur).
This probably helped Galli (and Zeus) because road cyclists were very conservative and many were appalled by the look, weight and complexity of C-Record. These cyclists warmed to Galli’s new, very retro design, with its traditional Campagnolo style adjustment screws.
Of course it couldn’t last - and it didn’t.
This gold version (it's all done in the best PAH-SIBBLE taste) weighs a very respectable 183g as the sprung pivot bolt is not steel although it is ‘chromed’ (possibly aluminium?). The hanger bolt is steel.