What follows here are basic comparisons betweent the various Sterling models. Please note that some components are interchangeable, and some early bodies have been modified with later components. Many thanks to Greg Hampton for the photos and his uncanny ability to locate bodies and components.
The basic Sterling body, the first and second generation cars, had not evolved much from the first Nova molds. Headroom was limited, and the body sat directly on an unaltered VW Beetle platform. Side scoops were low on the body and indented on top of the rear fenders just behind the cockpit.
The Sovran had the squared off wheel arches, sat on a full VW pan, featured pop-up headlights, larger canopy, wrap-around dashboard, larger side glass, but no more headroom than the early cars. Bottom side scoops were almost in the same position as early cars, but the fender scoops were moved to directly behind the cockpit and enlongated to almost a rectangle shape.
The GT by California Component Cars featured a one-piece monocoque body, rounded wheel arches, larger canopy, wraparound dashboard with integrated armrests and larger side glass. Bottom side scoops were raised higher due to the addition of the full fiberglass floor, and the fender scoops were the same from the previous Sovran design.
Dashboards were interchangeable between the series I and II cars; it's not unusual to see a straight style dash in an early numbered car. Sovran and GT dashboards, if found, could probably be made to fit, but were built to fit the deeper canopy dimensions.
An option that was available at least by 1977 was in the form of a factory T-top. Recognizing this factory option is easy - the T portion is recessed into the actual bodywork much like a production car. The tops themselves were well crafted with pivoting latches on either side. A few other options were the vented front bonnet as seen in the black Sovran above - great for a watercooled conversion, and a flat back hatch which was fitted with a glass window (see Sonny Halpain's page for an image).