I think you are almost right on here.

Imagine being able to scan a Holland and Holland royal stock and duplicate the action inletting to .005" with a CNC router!
How about duplicating ANY part of ANY gun to a tolerance of .005"?

The engraving would be nearly impossible to duplicate simply because of the differing angles and cut profiles hand engraving produces. Simple engraving would be easy to replicate, but it would have a different look than hand engraving.

I think this may have to be my next toy!