I think interior colours for the Lancaster are a bit of a minefield.
Early production certainly had interior green interiors, but these were often painted night/black, at least the forward section as far back as the navigators station at a major service interval. The A.V.Roe Co Ltd camouflage drawing Z1723 of 31/3/41 specifies only that 'the interior of the bomb compartment, undercarriage compartment including doors and interior of wing flaps are to be painted Night'. If you are making an early production aircraft, welcome to the minefield.
Later aircraft are generally assumed to have been completed with a black/Night forward section (and turret interiors), but I'm not convinced its as simple as that.
'F' Freddie at the IWM is supposedly in the condition in which it was taken out of service...and.
The bomb aimer's station is black/Night. Freddie is DV372, part of the third production batch from Metropolitan Vickers, delivered sometime between May and November
1943. I have read that different factories completed the aircraft with different finishes, but I can't comment on that (because I don't know). That area under the glass at the rear of the cockpit would have been finished in the Dark Green camouflage colour, and something has happened to that.
Unfortunately, there are few if any genuine colour images of Lancaster interiors from the period. Interpreting black and white images is always going to involve some assumptions and guess work.
The BBMF Lancaster (orig. PA474) is a very late production aircraft, part of the first production batch from Vickers-Armstrong Ltd Chester. The first were delivered in June 1944, the last in September 1945. It is obviously not in original condition, but the BBMF, certainly in the last twenty/thirty years, has made an effort to keep things looking as they would have done. I would not discount it as a reference.