One of the Girandoni airguns that I've been trying to obtain pictures of is the Girandoni copy made by Franz Thiele, Innsbruck, mentioned by Arne Hoff on p. 73, Airguns and other Pneumatic Arms.
Hoff mentions that this airgun was presented to the Elector, later the King Friedrich August of Saxony about 1800.
Fortunately, the director of the Innsbruck museum had a good contact at Dresden and was able to provide the following pictures.
The holding institution is Staatliche Kunstsammlungen Dresden
Of course, as can be seen, this is another of the same English-type Girandoni that has been modified by shortening the barrel, adding engraving on stock and receiver. It also has the lever-type decocking safety on the left side plate.