RJW NZ, you asked about the rear sight:
My external components that aren't close to original are; the bands-marked GEW, the cut off-a stock nomk3, rear sight-marked B (but proper/correct rear sight marks I don't know yet, did they make rear sights with EFD?)
This is how my No.1 mark VI is marked on the rear sight:
The rear sight is marked with an "E" superimposed on a "D"
The mark is found on the aperture slide on the left hand side and also on the top left front face on mine.