I don't have one to hand, but the engine nacelles that plug into the wing - they have a more rounded shape for the Hercules, which is a radial, and a Merlin 85 cowling is round. The difference is quite subtle but it is there. A look through the Lincoln Warpaint shows that the nacelle shape, certainly on the outboard ones if not the inners, is definitely a more rounded shape. Hence why Glenn specifies the Airfix Lancaster II.
Paragon gave some adaptors for the inners and new outer nacelles that were round at the front (the ones for his Lancaster II were similar) but TBH, I think they're underscale and the engines themselves have the wrong front and are also underscale. DB gave you vacform outer nacelles to go over the Airfix 1979 ones, Flightpath resin ones but neither gave you adaptors for the inner nacelles, you just have to use Milliput or another filler to fair it all in. Mind, there was a lot missing from the Flightpath conversion than there was in the DB one. Paragon,s may have been wrong in places but at least you got everything, and so did Blackbird. Although not enough for the RAAF ones as Red Roo did an expensive upgrade for an expensive conversion to go on a not entirely cheap Lancaster kit.
I'd suggest a read of Woody67's conversion from the Lancaster II with the Blackbird kit over on Britmodeller, if it hasn't been fubarred by the Photobucket snafu. It's very informative and quite handy in places. In addition, there's a Lincoln in Detail in SAM from either late 1989 or early 1990 that has a conversion from the 1979 tooling using the DB conversion.