Quite so. Furthermore, Ayde published his 'Pocket Gunner' in 1798 and he could not know how important foreign equipment would become to the French army. He died in 1808 as I remember. The ability to appreciate the relevance of particular sources to the argument in question is fundamental to historical analysis.
The other question that occurs to me is how familiar was Ayde with artillery other than British and French, and what were his prejudices and preferences - did he have any particular 'axes to grind?
I don't know the answer to that but we have seen it demonstrated on many, many occasions, here and elsewhere, that Gribeaval's equipment was far from unique, or technically superior to its peers.