That the 6-pounder and 24-pounder howitzer were produced in large numbers is not new information. It has been in English for over 20 years. However, the 4- and 8-pounders of the Gribeauval System were either sent into Spain or placed in the arsenals.
The Imperial Guard still had Gribeauval 4-pounders as late as 1811. The Gribeauval 12-pounders were still being employed, however.
Further, the 'system' was still in effect which is what is important. And besides ordnance and vehicles, that includes doctrine, training, organization, production methods, education, and the rest of what makes artillery able to operate. All of what was available was incorporated into the present artillery system for a united whole. That is the reason the French artillery arm was able to rapidly reform and rearm after the heavy losses in Russia and was prepared for the 1813 campaign by early April.
What had been institutionalized by Gribeauval and his successors was military excellence. What is usually overlooked when studying the period is the French reform movement after the Seven Years' War. It was much greater and more comprehensive than the Prussian reform movement in 1807-1813 and on a much grander scale. And it survived the devastation of the French Revolution.
That's too bad about the references and notes. I have always found them very useful and I usually like to peruse the bibliography and notes before reading the text. Maybe in your further work you'll remember to include them.