The OP's questions have been muddied.

The Dickson is not the same internally as the DMB.
The "Edinburgh Gun" is a bar-in-wood MacNaughton. Not DMB or Dickson.

Each of the designs has evolved over time. I believe they all migrated to Southgate ejectors, for instance, but originally the older guns had other styles of ejectors.

Also, the skeletonized MacNaughton, while beautiful, with it's bar-in-wood design, is prone to stock cracking on the bottom.

Out there doing it best I can.