This post has been a little confusing to me. If the goal is everything must be original as built, then you can't do a rebuild. If the goals is OEM original, folks are really only going to see exterior parts and matching numbers block and exterior components are the most important. Certainly having a good reputable Mopar guy do the work. Internally, if not really worn, original valves maybe salvage, heads cleaned up, seats corrected, who cares if the springs are new.

Minimal work to the engine if possible. Frankly, you can still find good original pistons and rods if necessary.

Engine builder I help is freshening up for performance a 73 440. Basically only needed a cylinder honing, though it probably did not have 100K on the motor. Resized the rods, added a forged crank instead of cast, better valve springs and moved to early 440 stock high compression pistons and a mild cam. You can even get bearing and seal to rebuild the water pump. But I bet it is not original anyway at 100K and 47 years. Do you want to trust the oil pump or do you go with new, but use your old housing and just swap ring and impeller... Nothing wrong with a OEM rebuild with new rotating parts. Obviously if a survivor car or going for a gold standard, all NOS parts would be used, but cost goes through roof.

Frankly no one will know what was done internally unless you show them documentation and pictures.