Εύρηκα!

A friend of the NS has located the accession record from Le Musée royal de l'Armée et d'Histoire militaire (Belgium) for a 24lb cannon cast in 1807. It has the “chiffre de Louis-Napoléon de Holland” [“L N couronné”]! He is also preparing a collection of photographs, drawings, book pages and accession records of materials from his collection concerning Dutch artillery from collections in England, Belgium, Moscow, Borodino and Sweden. I will post this material on the NS when it is prepared:

Accession record for 24lb cannon cast in Den Hagen by L & J Maritz in A° 1807:
https://drive.google.com/file/d/1VPY3pM1ytXucjif03uSFdzPWxfCxthPj/view?usp=sharing
https://gallica.bnf.fr/ark:/12148/bpt6k6501530k/f274.item.r=76
See p. 261-265 for other Dutch pieces.