Salaams Ole S,
There is still a wheel lock rifle of Valentin Klett existing in the German Hunting Museum in Munich. But also other European museums have old Klett rifles on display: the Windsor Collection includes the oldest rifle with insert barrel from Sigmund Klett from 1652. Further examples of him and Cornelius Klett are shown in the Museum of Baden and respectively in the Metropolitan Museum of New York. And Sotherby's auctions catalogue of June 1991 called on an "extremely rare quad barreled percussion-revolving-pair" manufactured by Paul Klett in 1680 for 20,000 £. See
http://thomasdelmar.com/Catalogues/a.../lot0302-0.jpg As in your example he signed his work VK. Very interesting about the signature being required to be a sign or token ... from Old German zeihhan (“sign, symbol”)
Regards,
Ibrahiim al Balooshi.