![Image](https://i.postimg.cc/Y99KyTmh/Mk-1-and-Mk-2-body-designs.jpg)
I have not detailed the flap on my illustration above, but body castings classed as Mk1 have a flap slightly squarer and higher up the rear wing so is a bit further away from the bumper.
Mk1 bodies have the larger door locks as detailed above.
Ghosthunter.