Hi guys....
The chap to talk to is Alan Faulkner Stevens. He is the ACOC registrar for Mk IV Cobras and very knowledgable. And, very important, get the right literature beforehand. Mk IVs were produced over a period of some 10 years, from mid eighties.
Differences do exist as to engine specs, trim, minor body items like scoops or no-scoops, short vs long nose, bumper set-up, rear fender lips, dashboard and interior trim, some in direct correlation to the period of production, some in correlation to overall configuration and chassis numbering AK.... cars, AKL.... cars, proper lightweight spec AKL.... cars with upgraded engines, 15 vs 16 inch wheels, anti-roll bars, roll hoop and other minor features .... I'm not sure if any of these differences are scientifically recorded.
Normally you start the other way: having found a Mk IV for sale, you try to find out about its history and set-up.
So first thing to do is to check chassis number against the register and some typical features to ensure that you really look at a genuine AC Mk IV. Photos of details help a lot to identify a car.
Hope this is of any assistance to you to start with.
Best regards
Constant