The Grey Green frames I mentioned are the wing ribs, above the wheel wells, inside the wing.
These would be difficult to see, even in 1/48th scale, without turning the model upside down and using a torch, and virtually impossible to replicate in 1/144th scale, due to the constraints of plastic thickness (of the wing halves and nacelles) and moulding process. For your model, painting the entire wheel well interior matt black will be adequate.
I do have some photos looking way up into the wells on a real Lanc, but trying to scan them would damage the spines of the books they're in. However, the extract from the HK Models Lancaster instructions, shows these ribs (blue arrows).
The other photos show the front and rear views into the wheel wells of a Lincoln, which is virtually identical to the Lanc in layout - notice how dark it is in there, even with the use of flash, and that the "roof" of the well (actually the inner surface of the wing upper skin) is also black.