The Gambato Gran Sport series is a set of Argentinian 'derivatives' of classic Campagnolo models. While I am extremely unclear about the dates, I consider that they can be roughly grouped into three groups:
The oddity is that, in each case, the Gambato models seem to date from about a decade after the relevant Campagnolo originals. It seems that the designs got lost in some kind of Argentinian time warp - perhaps in the boot (trunk) of a DeLorean.
This Gambato Gran Sport belongs to the third series listed above. The knuckles are chunky and plastic and the b-knuckle has a screw to control the extent of motion of the b-pivot, but this screw is perpendicular to the plane of rotation. This is weird but very similar to the arrangement on a Simplex SX1.
Overall, the derailleur is an interesting blend of a basic, clunky, inexpensive derailleur and rather highly decorated parallelogram plates. I like it.
This example has a short, polished silver, pulley cage.