I believe that this sentence only refers to the particular party that Mack was supposed to lead.
From Haller "Am 10. October 1787 gingen 200 Stück der neuen Kriegswaffe mit allem Zubehör zu Wasser nach Peterwardein ab. "
The soldiers these guns were intended for were the Grenz sharpshooters who were going to participate in the action. A number of officers and corporals were ordered to Peterwardein for training by Mack. Peterwardein was the supply fort for the Belgrade assault.
It is important to understand that this thesis is not about the airguns; it is about Mack. There is a lot of information about airgun history that it does not contain nor would there be any reason for that information to be there. What is remarkable about this thesis is the level of planning detail contained in Mack's plan for the sneak attack; it reads like a play. (Which is a typical aspect of Mack's planning in that there was no anticipation of things going wrong and planning alternatives.) This raid is an all but unknown event in history. There were only a few mentions in regimental histories of a Belgrade plan that failed (twice) but that's about it. This thesis opened up a new page of history for the Austrian Military Airgun but it doesn't begin to tell the entire story.
The AMA fell out of favor with the army after 1788-1789; it was next used by the Tyrolean Sharpshooters during 1793-1795 France. This use was specific to the Austrian specialist siege group. The specific application was the third parallel were the Tyrolleans (famous for being unusually good shots) would pick off any Frenchmen brave enough to show themselves.
The next known usage was another attempt of a coup de main at Legnano in 1796 that was a virtual replay of Belgrade 1787. It too failed. The AMA was seen by some in the Austrian military (most importantly Francis I) as a valuable tool for secret night operations. Only two of these operations are known of but that is the nature of secret operations.. . they tend to be secrets. Knowing the nature of Francis I, it's almost certain that he found other dark uses for his silent killer that we will never know about.
Where the military airgun found it's home was in the Genie Korp. The defense of Castle Graz in 1809, led by a Genie Korp officer, included 24 airgun shooters in the order of battle. Upon surrender, there was a signed inventory of all material turned over to the French that included 6 airguns with all accessories. Airguns have a distinct advantage in defense of fortresses. The first use of an airgun is suggest by a siege expert circa 1760. The greatest advantage is in underground/mining/countermining operations where use of a regular firearm is all but impossible. Airguns are included in Genie Korp manuals as late as 1862.
Airguns were never widely used even when fielded in 1788-1789. Then when Joseph II died in 1790 chances of any wider use was extremely limited. It became a specialist tool.
Note that in 1810 even N. considered the use of the airgun for the underground war and tests were made and a LePage "Girandoni" was made (I have pictures of this gun) When the report was presented to N. he rejected it; ordered all reports destroyed and the guns sent to the museum. See Statique de la Guerre by Baron Révéroni de Saint-Cyr
The first paragraph reads, "L’auteur de ces Mémoires a été chargé, en 1810, par le général Marescot, premier inspecteur du corps du génie, de l’examen et de l’utilité du projet d’armer les mineurs attachés à ce corps, avec des fusils à vent, pour la guerre souterraine. On lui a remis à cet effet un fusil modèle ou carabine à vent prise sur les tirailleurs autrichiens et tyroliens, qui s’en servaient fréquemment. En conséquence, le lieutenant-colonel de R** a fait faire des essais de cette arme par le sieur Lepage, arquebusier de Bonaparte, et des expériences réitérées. Elles ont amené des résultats si prompts, si précieux pour la guerre, que l’auteur s’est déterminé à proposer d’en armer non-seulement le mineurs, mais toute l’infanterie légere, et à produire un Mémoire à l’appui de cette innovation."
My opinion is that N. rejected the French airgun because Saint-Cyr went off the rails by suggesting, a la Joseph II, equipping entire infantry units with airguns instead of staying on the assigned task. The airgun for the sappers/miners makes perfect sense and was worth looking into. Upon receiving a report suggesting mass use of the airguns in the field, I would have tossed it right back at the authors and kicked them in the behind a la N.