Her's a serious parts question to get your teeth into! As far as I am concerned, there is no definitive Mk.1 240Z as many of the changes of specification took place at different dates. The process is one of gradual evolution rather than a major face-lift operation. From memory and with the aid of the trusty parts book, I think the major areas are as follows:
Grilles and tailgate vent system up to 01/71. As far as I am aware, this probably only applies to a very small handful (2?) U.K. cars. The change was accompanied by revised rear quarter panels with ventilation holes and a change of rear quarter emblem from 240Z script to circular, perforated and just "Z". The early hub caps (black and chrome with central "D") are probably only correct on these very early cars.
Also in 01/71, the changes to the rear floor area were implemented to bring in the storage bins. Previously the floor just had round perforations and plastic covers over tools and jack. The fuel filler flap and lock changed at this time.
Hard to quantify, but I think there were some subtle trim changes in 01/71 also. Tailgate lock had already been changed by 06/70!
The early centre console is valid to 08/71, as is the steel fan blade. The fan was then replaced with the resin version.
Also in 08/71 the brake master cylinder was changed from the early type with front disc reservoir at the far end of the cylinder to the later type which runs on through the 260Z where the disc reservoir is at the servo end. Rear driveshaft and differential position/layout was revised at this time - different front and rear crossmembers and different front differential mount.
Vertical lines on the HRW continue until 01/72 when they were replaced by horizontal. The old part number supercedes to the horizontal version, so no chance of getting a new vertical type!
In 07/72, the GRP headlamp cowl panels were replaced by steel ones and the layout of the dashboard was revised in the minor switches (hazard switch?). Also at this time, the rear wheel cylinders were revised (although the later ones can be retro-fitted) and the brake proportioning valve was moved from the rear of the car to a position on the O/S bulkhead (different valve and pipework layout with this system).
Also, the front grille and its attachment points were revised which also means that the centre valence panel and front crossmember are different. Door hinges were revised at this time, but I don't know in what way....
