Hey Robbie!  Perhaps there is an easier solution for the replicas.
There's no problem for the not very good replica: anyone can see the
difference.

For a "replica?", or an invention or improvement of any existing
instrument, the original name can be changed.  For example, Ferdinand
Schlenker, a mechanical music enthusiast in Germany, brought forth from
a Weber-Unika a Weber-Styria.  But it is not exactly like the original
so we have no chance to confuse it.

For a very exact replica, bearing the name of the original firm,
why not place a number inside to identify the year or the maker (in
a defined location), different from the original number.  You cannot
prevent somebody else removing this new number, but if the case is
later damaged at the place defined for the identity number, you can
have a doubt.

For the instruments made by S. Wendel there is no doubt: they are now
very well-known, the number, the style and so on.  He makes enough
advertisements too.  And now with the Phillips Paganini Orchester
monster, no problem -- you have only one in the world today: the new
one!

As for the "pottering" about an old instrument, it is the same now as
at a flea-market: you must know the matter or estimate the doubt with
a pinch of luck.  The very good speculations come with experience:
so to speak, learned with many errors in the past!

Best regards from Mirecourt in France

Francoise Dussour

 [ to potter, or to putter (USA): to busy oneself with trifles.
 [ But maybe a work of art or a useful machine will be conceived at
 [ the hands of the potter (pottery maker) or the tinkerer (tinsmith).
 [ -- Robbie