Yes, during WW2, the seat was as shown. Here's another pic, showing the very dark brown leather 'slip on' rear padding. This one has been restored - during WW2 the leather was very dark, almost black.
The seat mounts were the same colour as the rest of the cockpit - Grey Green.
Note that in the colour pick of Johnson, he's wearing British Army 'Battledress'. This was common among 2 TAF and other close-support or fighter crews during this period, in case of forced landing or bail-out etc, as the RAF uniform could easily be confused with the German uniforms, which lead to a number of aircrew being shot by 'friendly' forces or Resistance.