Well, actually it's not. A copy might not be made
of the same materials
that the original was made of. It might have different components because
the originals may not be manufactured anymore. Minute details like the
features of the case, or the layout of the PCBs may be inaccurate, or the
wrong color, or the traces the wrong width. Etc.
I'm one of the few that could build a large number of old systems using
parts on hand with correct date codes. Active scrounging back then.
It's not had in most cases to copy something like an altair or imsai
verbatum.
Then again when I had to replace a 7451 in the FP of my 8F, the only ones
I had predated the machine by a few years! That will no doubt make a few
wonder...
Allison