For sure, one can get as deep into a bench copy as one wishes.
Would you look for wood with near identical curl or figure?
Would you reproduce dings and scratches exactly?
If it was converted to percussion then reconverted would you make it flint,,then put in a drum and nipple and convert the lock, then reconvert to flint?
All this sounds facetious but these are decisions to make. I’d start with a mission statement for the project.
This could be, “to create a longrifle with the same architecture, carving, dimensions, furniture, construction details, small parts, and so on with a lock and barrel closely resembling the original gun.”
Another approach is to not do a bench copy but “the next one that maker made after gun X.” This allows differences in barrel, lock, small details. It requires similar study and dedication. For example, making not just a “Dickert” but “a Dickert like RCA 48.”