There was never any requirement for sharing anything between the two vehicles and they were made by completely different contractors. Grumman made the LEM and North American Aviation made the command module. There was also a significant redesign of the command module after the Apollo 1 fire which completely changed the cabin environment. Sort of how you probably cannot take a chunk of equipment out of the cockpit of an Airbus 320 and expect to slot it in to a similar role in a Boeing 737.