The Pinin Farina-bodied cabriolet that Ferrari introduced at the Geneva Motor Show in March 1957 was not only a triumph of design, with its elegant rear haunches, covered headlamps, and long centrally ventilated bonnet, but it was also the car that marked an auspicious milestone in Maranello history as the company’s first series-produced open-top model.

While the first two examples were essentially prototypes that visibly varied, sometimes referred to as the Pinin Farina Spiders, the next 38 cars were generally more uniform in design with several different specific variations.

However, despite being the first series-built Ferrari convertible, many experts still consider the Series I Cabriolets to be virtual one-offs, as they were constructed in Pinin Farina’s custom shop rather than on the coachbuilder’s factory floor.

Featuring a myriad of customized trim details and differing interior amenities, these cars varied significantly enough from example to example to support the idea tha...