Hi Brendan, The vents are part of the Vintage pack which Maserati offered. Not many have the pack so quite a nice addition.
Here's what the pack included as posted by AndyK...
This was the Vintage pack offer at its launch at the New York Motorshow..
Chromed front grill
Front Maserati Trident with hand-painted red accents
Chromed side fender vents
Chromed door handles
Wheels with special "Ball polished" treatment enhancing the mechanical characteristics while donating a brilliant effect
Silver colored brake calipers
To make the personalization of the exterior of the Spyder complete, with the Vintage package it is possible to add chromed rearview mirrors and chromed roll bars.
The personalization kit can be further enriched by internal elements, available as individual options:
Aluminum racing pedals complete with vintage-style Maserati trident
Central consolle, door trims and paddle shift levers finished in aluminum
Gauge cluster finished in traditional 1950s Maserati racing light blue with style digits