Many years ago, I bought a second hand glovebox for my 1980 DHC. Compared to the glovebox and dashboard in my wedge, it's much lighter. They all look original, as in the textures are the same and there's no sign of them having been repainted.
Was there more than one shade of grey dashboard to come out of Canley or Solihull? I believe black dashboards only came out of Speke?
I Have a Canley 1980 with grey dashboard. I bought a replacement console cubby and when I got it the tint of the part was slightly off. I'm guessing the part may have come off a Solihull car, either that or possibly bleaching from the sun.
I don't know if there were different shades of grey used, I personally doubt it. But you never know with BL! And when you look closely you'll notice that all dashboards were produced in black with the later ones sprayed grey. Different shades probably caused by the sun and/or dirt. Try a good clean and see what comes out!