"There is no such thing as a perfect replica model of anything"
There is an acceptable reproduction of the prototypes, in the marketplace, i.e. - Gibson makes Les Paul Custom guitars, and Fender makes Stratocasters. There is specific tooling and materials that are used, over and over again, to manufacture these quality musical instruments.
GE Transportation, offers an Evolution series of locomotives; plus, other repeated models. They can provide numerous replica stock models or customize... for an additional charge.
They don't redesign a model every time they build a locomotive, for a customer.
A design is accepted, blueprints are created, the construction materials are acquired, orders are taken; and then, the manufacturing process begins...
So, when I place an order for a Black Les Paul Custom, with ivory colored trim... that's what I get - Humbucking pickups and all the other standard features.
Sure, there are knockoff manufacturers offering cheaper versions of a Les Paul Custom; but, most serious musicians pay the higher price, for the original high quality guitar.
Rick