I appreciate all the thoughtful responses.
Per Robc's comments, perhaps "Hand-crafted" is a more accurate overall descriptive term than "hand-made"?
And under the definition "hand-crafted," the chief requisite would be "hand-fitted."
Yet, I also think "hand-filed" should be part of the description -- at least in describing the British/European gunmaking tradition, as the major components (action and furniture, etc.) were all "touched by the file" and often extensively so.
Kensal made a good point about 'interchangeability." When I initially posted I was referring to it in the way 19th Century British observers would have regarded the "American System of Manufactures" where practical interchangeability would have been the goal.
The problem with definitions is they change over time: interchangeability in the 1870s meant something different than in 1940 and again in 2000. So ... what about the inclusion of the term "non-standardized" parts instead of "non-interchangeable"?
My goal is to use language as precisely as possible—in this case describing hand-crafted guns before the CNC revolution. The latter (CNC) is again changing what we mean by hand-crafted, but maybe that's another topic....
Insights, Arguments? (Thanks)