Classic Confusion

I am badly confused by adverts referring to Range Rover 'Classic' - I have early (78) 2 door (= with the handle on the rear vertical edge of the door), clearly this fashion changed at some point, no doubt along with many other features, can someone guide me to a reference that would indicate how long the 'Classic' Range applied ( is it prior to P38?) and how and what the changes rung were during its development, I think there is a real chance of picking up bits for a Classic that would not be relevant to my early beast.

Strictly speaking the "Classic" term applies to all pre P38 Range Rovers sold after the P38 was introduced. I believe someone had the job of going round the factory car parks sticking Classic badges on all unsold stock.
The term is usually applied to all pre-P38 Range Rovers.