Yes, it would be the same engine in the Lancaster Mk.I and the Hurricane Mk.II, and indeed in the Halifax Mk.II. Check also Beaufighter and Wellington. With the Hercules, the Merlin XX was intended to become the RAF’s standard engine, mass produced by Ford. However there were problems fitting it to the Spitfire, requiring too much disruption of the production line, so there it was overtaken by the single speed Merlin 35.