alpacca is a trade name belonging to berndorf for their silver substitute. it is nickel silver, aka "paktong" "baitong" "white copper", originating in china and known in europe since the end of the 16thc. in 1823 the germans held a competition to see whose alpaca would most closely resemble silver. a number of factories produced it and used it in domestic omplements as well as musical instruments. alpaca as used fraudulently to create expensive "silver" trumpets etc. as well as morgan dollars - might be worth your while to get your library to hunt down a book on such marks - if it exists. these may be available on inter-library loan, as well.
if you are struck by the number of german books on the subject - alpacca was developed and heavily used in the german states for everything from frets to medals.

Alpacca-Silber (Bestecke) vom Goldenen Vliess. (2 Prospekte).
WÖTZEL & CO. GmbH. -:
Published by Aue in Sachsen. (Um 1934)., 1934
Preisliste 314 für Wello-Chrom-Bestecke (Verchromtes Original-Wellner-Alpacca).
WELLNER August SÖHNE SÄCHSISCHE METALLWARENFABRIK AG. -:
Published by Aue in Sachsen. Oktober, 1931
Spezialität: Alpacca naturpolierte und Alpacca-Silber-Tafelbestecke.
GRIMM Otto Kurt SILBERWAREN-GROSSHANDLUNG -:
Verlag: Reichenbach i. Vogtland. Ausgabe (1925)
Lebensfreude (Bestecke und Tafelgeräte aus Alpacca - Silber).
Wellner
Verlag: Aue Wellner ca (1935)
Bavaria-Bestecke Alpacca-Versilbert.
BAYERISCHE ALPACCAWARENFABRIK AG. -:
Published by Neu-Ulm a. d. Donau. (Um 1937)., 1937
Berndorfer Metallwarenfabrik Arthur Krupp A. G.
Published by Berndorfer Metallwarenfabrik Arthur Krupp A. G., Berndorf, Austria, 1930
Articoli casalinghi di metallo nichelato, argentato e di alpacca.
Grandi Empori Ottorino Bassetti. Pisa
Posateria e vasellame di alpacca argentata e naturale.
Argenteria Wellner. Firenze -
Wellner-Silber" - ein alter Begriff für schwerversilberte Alpacca-Bestecke. [Umschlagtitel abweichend:] Original-Wellner Bestecke.
Published by [Aue für] Berlin [Sächsische Metallwarenfabrik August Wellner Söhne für] Heinrich Ellinghausen Uhren und Goldwaren ohne Jahr [], 1929
Preis-Courant über Kirchen-Geräthe der k.k. priv. Alpacca- und China-Silber-Waaren-Fabrik von W. Bachmann &Co.
ANONYM)
Verlag: Wien, Eigenverlag, u. 1890: (1890)
Prontuario Peso dei Metalli. Lastre - Dischi - Tubi - Angolari - Piatti - Tondi - Reti - Funi, ecc. Alluminio - Alpacca - Argento - Atesia - Bronzo - Ferro - Ghisa - Nickel - Ottone - Piombo - Rame - Stagno - Zama - Zinco (170 tabelle). Con 42 tabelle di corrente uso riguardanti la Matematica, Meccanica, Chimica, e Fisica e 8 tabelle con la composizione delle leghe metalliche più note.
HOEPLI - METALLI) COMOLETTI, Giuseppe
more at google.de"Albert+Huttenlocher+Bijouterie-+und+Alpacca-Warenfabrik"